diff --git a/Cargo.toml b/Cargo.toml
index 1b5b117..94b28bd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,6 +2,7 @@
 name = "schematics"
 version = "0.1.0"
 authors = ["Adrian Heine <mail@adrianheine.de>"]
+edition = "2018"
 
 [dependencies]
 users = "0.7.0"
diff --git a/src/command_runner.rs b/src/command_runner.rs
index 934ee23..0b17ad0 100644
--- a/src/command_runner.rs
+++ b/src/command_runner.rs
@@ -150,7 +150,7 @@ impl<'a, U: AsRef<str>, C: CommandRunner> CommandRunner for SetuidCommandRunner<
 #[derive(Debug)]
 pub struct SuCommandRunner<'a, C>
 where
-  C: 'a + CommandRunner,
+  C: CommandRunner,
 {
   command_runner: &'a C,
   user_name: &'a str,
diff --git a/src/factory.rs b/src/factory.rs
index 1aedea2..71aabfc 100644
--- a/src/factory.rs
+++ b/src/factory.rs
@@ -1,18 +1,20 @@
 use regex::Regex;
 
-use command_runner::CommandRunner;
-use loggers::StdErrLogger;
-use repository::SymbolRepository;
-use resources::Resource;
-use schema::{NonRepeatingSymbolRunner, ReportingSymbolRunner, RequirementsResolvingSymbolRunner};
-use symbols::dir::Dir;
-use symbols::list::List;
-use symbols::owner::Owner;
-use symbols::systemd::user_session::SystemdUserSession;
-use symbols::tls::{TlsCsr, TlsKey};
-use symbols::user::SystemUserAdder;
-use symbols::user::{User, UserAdder};
-use symbols::{Symbol, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::loggers::StdErrLogger;
+use crate::repository::SymbolRepository;
+use crate::resources::Resource;
+use crate::schema::{
+  NonRepeatingSymbolRunner, ReportingSymbolRunner, RequirementsResolvingSymbolRunner,
+};
+use crate::symbols::dir::Dir;
+use crate::symbols::list::List;
+use crate::symbols::owner::Owner;
+use crate::symbols::systemd::user_session::SystemdUserSession;
+use crate::symbols::tls::{TlsCsr, TlsKey};
+use crate::symbols::user::SystemUserAdder;
+use crate::symbols::user::{User, UserAdder};
+use crate::symbols::{Symbol, SymbolRunner};
 
 #[derive(Default)]
 pub struct Factory {}
@@ -40,7 +42,7 @@ impl Factory {
   }
 }
 
-pub struct DefaultSymbolRepository<'a, A: 'a + UserAdder, C: 'a + CommandRunner> {
+pub struct DefaultSymbolRepository<'a, A: 'a + UserAdder, C: CommandRunner> {
   user_adder: A,
   command_runner: &'a C,
 
diff --git a/src/lib.rs b/src/lib.rs
index 46a700b..dcc5a68 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -19,9 +19,6 @@ missing_debug_implementations
 */
 #![allow(box_pointers)]
 
-extern crate regex;
-extern crate users;
-
 #[macro_use]
 mod for_each_tuple;
 
diff --git a/src/loggers.rs b/src/loggers.rs
index 0ad3c0d..0569c28 100644
--- a/src/loggers.rs
+++ b/src/loggers.rs
@@ -2,8 +2,8 @@ use std::io::stderr;
 use std::io::Write;
 
 pub trait Logger {
-  fn write(&mut self, &str);
-  fn debug(&mut self, &str);
+  fn write(&mut self, msg: &str);
+  fn debug(&mut self, msg: &str);
 }
 
 pub struct StdErrLogger;
diff --git a/src/repository.rs b/src/repository.rs
index 943590b..5634b41 100644
--- a/src/repository.rs
+++ b/src/repository.rs
@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 
-use resources::Resource;
-use symbols::Symbol;
+use crate::resources::Resource;
+use crate::symbols::Symbol;
 
 pub trait SymbolRepository<'a> {
   fn get_symbol(&'a self, resource: &Resource) -> Option<Box<dyn Symbol + 'a>>;
diff --git a/src/schema.rs b/src/schema.rs
index 2489c74..7f12f9c 100644
--- a/src/schema.rs
+++ b/src/schema.rs
@@ -2,9 +2,9 @@ use std::cell::RefCell;
 use std::error::Error;
 use std::fmt;
 
-use loggers::Logger;
-use repository::SymbolRepository;
-use symbols::{Symbol, SymbolRunner};
+use crate::loggers::Logger;
+use crate::repository::SymbolRepository;
+use crate::symbols::{Symbol, SymbolRunner};
 
 #[derive(Debug)]
 pub enum SymbolRunError {
@@ -28,7 +28,7 @@ impl Error for SymbolRunError {
 }
 
 impl fmt::Display for SymbolRunError {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     match self {
       SymbolRunError::Symbol(ref e) => write!(f, "{}", e),
       SymbolRunError::ExecuteDidNotReach(_) => write!(f, "{}", self.description()),
@@ -98,7 +98,7 @@ impl<L: Logger> SymbolRunner for DrySymbolRunner<L> {
   }
 }
 
-pub struct ReportingSymbolRunner<'a, R: 'a + SymbolRunner, L: Logger>(&'a R, RefCell<L>);
+pub struct ReportingSymbolRunner<'a, R: SymbolRunner, L: Logger>(&'a R, RefCell<L>);
 
 impl<'a, R, L> ReportingSymbolRunner<'a, R, L>
 where
@@ -131,7 +131,7 @@ where
   }
 }
 
-use resources::Resource;
+use crate::resources::Resource;
 use std::collections::HashSet;
 
 pub struct NonRepeatingSymbolRunner<R: SymbolRunner> {
@@ -171,12 +171,11 @@ impl<R: SymbolRunner> SymbolRunner for NonRepeatingSymbolRunner<R> {
 }
 use std::marker::PhantomData;
 
-pub struct RequirementsResolvingSymbolRunner<
-  'a,
-  's,
-  R: 'a + SymbolRunner,
-  G: 'a + SymbolRepository<'s>,
->(R, &'a G, PhantomData<Box<dyn Symbol + 's>>);
+pub struct RequirementsResolvingSymbolRunner<'a, 's, R: 'a + SymbolRunner, G: SymbolRepository<'s>>(
+  R,
+  &'a G,
+  PhantomData<Box<dyn Symbol + 's>>,
+);
 
 impl<'s, 'a: 's, R, G> RequirementsResolvingSymbolRunner<'a, 's, R, G>
 where
@@ -211,10 +210,10 @@ mod test {
   use std::error::Error;
   use std::fmt;
 
-  use loggers::Logger;
-  use schema::InitializingSymbolRunner;
-  use schema::SymbolRunner;
-  use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction};
+  use crate::loggers::Logger;
+  use crate::schema::InitializingSymbolRunner;
+  use crate::schema::SymbolRunner;
+  use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction};
 
   #[derive(Debug, PartialEq, Clone)]
   enum DummySymbolError {
@@ -228,7 +227,7 @@ mod test {
   }
 
   impl fmt::Display for DummySymbolError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
       write!(f, "Dummy symbol error")
     }
   }
@@ -259,7 +258,7 @@ mod test {
   }
 
   impl<'a> fmt::Display for DummySymbol<'a> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
       write!(f, "Dummy symbol")
     }
   }
diff --git a/src/symbols/acme/account_key.rs b/src/symbols/acme/account_key.rs
index 3ab2099..dc1fac4 100644
--- a/src/symbols/acme/account_key.rs
+++ b/src/symbols/acme/account_key.rs
@@ -2,9 +2,9 @@ use std::error::Error;
 use std::fmt;
 use std::path::Path;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct AcmeAccountKey<'a, P: AsRef<Path>, C: CommandRunner> {
   path: P,
@@ -25,7 +25,7 @@ impl<'a, P: AsRef<Path>, C: CommandRunner> AcmeAccountKey<'a, P, C> {
 }
 
 impl<'a, P: AsRef<Path>, C: CommandRunner> fmt::Display for AcmeAccountKey<'a, P, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "AcmeAccountKey {}", self.path.as_ref().display())
   }
 }
diff --git a/src/symbols/acme/cert.rs b/src/symbols/acme/cert.rs
index e3f46cb..d3081a8 100644
--- a/src/symbols/acme/cert.rs
+++ b/src/symbols/acme/cert.rs
@@ -4,9 +4,9 @@ use std::fs::File as FsFile;
 use std::io::Write;
 use std::path::PathBuf;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct AcmeCert<'a, D: AsRef<str>, C: CommandRunner> {
   domain: D,
@@ -31,7 +31,7 @@ impl<'a, D: AsRef<str>, C: CommandRunner> AcmeCert<'a, D, C> {
 }
 
 impl<'a, D: AsRef<str>, C: CommandRunner> fmt::Display for AcmeCert<'a, D, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "AcmeCert {}", self.domain.as_ref())
   }
 }
diff --git a/src/symbols/acme/chain.rs b/src/symbols/acme/chain.rs
index 5ee8921..ef0585f 100644
--- a/src/symbols/acme/chain.rs
+++ b/src/symbols/acme/chain.rs
@@ -4,9 +4,9 @@ use std::fs::File as FsFile;
 use std::io::Write;
 use std::path::PathBuf;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct AcmeCertChain<'a, D: AsRef<str>, C: CommandRunner> {
   domain: D,
@@ -31,7 +31,7 @@ impl<'a, D: AsRef<str>, C: CommandRunner> AcmeCertChain<'a, D, C> {
 }
 
 impl<'a, D: AsRef<str>, C: CommandRunner> fmt::Display for AcmeCertChain<'a, D, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "AcmeCertChain {}", self.domain.as_ref())
   }
 }
diff --git a/src/symbols/acme/user.rs b/src/symbols/acme/user.rs
index 208a21b..6a74780 100644
--- a/src/symbols/acme/user.rs
+++ b/src/symbols/acme/user.rs
@@ -1,12 +1,12 @@
 use std::path::{Path, PathBuf};
 
-use command_runner::CommandRunner;
-use symbols::acme::AcmeAccountKey;
-use symbols::dir::Dir;
-use symbols::file::File;
-use symbols::list::List;
-use symbols::owner::Owner;
-use symbols::Symbol;
+use crate::command_runner::CommandRunner;
+use crate::symbols::acme::AcmeAccountKey;
+use crate::symbols::dir::Dir;
+use crate::symbols::file::File;
+use crate::symbols::list::List;
+use crate::symbols::owner::Owner;
+use crate::symbols::Symbol;
 
 pub fn new<'a, R: CommandRunner, C: 'a + AsRef<str>, U: 'a + AsRef<str> + Clone, H: AsRef<Path>>(
   command_runner: &'a R,
diff --git a/src/symbols/cron.rs b/src/symbols/cron.rs
index 1e68da6..492e5b4 100644
--- a/src/symbols/cron.rs
+++ b/src/symbols/cron.rs
@@ -1,9 +1,9 @@
 use std::error::Error;
 use std::fmt;
 
-use command_runner::CommandRunner;
+use crate::command_runner::CommandRunner;
 
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct Cron<'r, C: AsRef<str>, U: AsRef<str>, R: CommandRunner> {
   user: U,
@@ -54,7 +54,7 @@ impl<'r, C: AsRef<str>, U: AsRef<str>, R: CommandRunner> Symbol for Cron<'r, C,
 }
 
 impl<'r, C: AsRef<str>, U: AsRef<str>, R: CommandRunner> fmt::Display for Cron<'r, C, U, R> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "Cron {}", self.user.as_ref())
   }
 }
diff --git a/src/symbols/dir.rs b/src/symbols/dir.rs
index 7eb33ef..34d3757 100644
--- a/src/symbols/dir.rs
+++ b/src/symbols/dir.rs
@@ -4,8 +4,8 @@ use std::fs;
 use std::io;
 use std::path::Path;
 
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct Dir<D: AsRef<Path>> {
   path: D,
@@ -64,7 +64,7 @@ impl<D: AsRef<Path>> Symbol for Dir<D> {
 }
 
 impl<D: AsRef<Path>> fmt::Display for Dir<D> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "Dir {}", self.path.as_ref().display())
   }
 }
diff --git a/src/symbols/factory.rs b/src/symbols/factory.rs
index 58b20a8..f654b5f 100644
--- a/src/symbols/factory.rs
+++ b/src/symbols/factory.rs
@@ -2,22 +2,22 @@ use std::borrow::Cow;
 use std::path::Path;
 use std::path::PathBuf;
 
-use command_runner::{CommandRunner, SetuidCommandRunner};
-use storage::{SimpleStorage, Storage};
-use symbols::acme::{newAcmeUser, AcmeCert, AcmeCertChain};
-use symbols::cron::Cron;
-use symbols::file::File;
-use symbols::git::checkout::GitCheckout;
-use symbols::hook::Hook;
-use symbols::list::List;
-use symbols::mariadb::{DatabaseDump, MariaDBDatabase, MariaDBUser};
-use symbols::nginx::server::{server_config, NginxServer};
-use symbols::owner::Owner;
-use symbols::stored_directory::{StorageDirection, StoredDirectory};
-use symbols::systemd::reload::ReloadService;
-use symbols::systemd::user_service::UserService;
-use symbols::tls::SelfSignedTlsCert;
-use symbols::{Symbol, SymbolRunner};
+use crate::command_runner::{CommandRunner, SetuidCommandRunner};
+use crate::storage::{SimpleStorage, Storage};
+use crate::symbols::acme::{newAcmeUser, AcmeCert, AcmeCertChain};
+use crate::symbols::cron::Cron;
+use crate::symbols::file::File;
+use crate::symbols::git::checkout::GitCheckout;
+use crate::symbols::hook::Hook;
+use crate::symbols::list::List;
+use crate::symbols::mariadb::{DatabaseDump, MariaDBDatabase, MariaDBUser};
+use crate::symbols::nginx::server::{server_config, NginxServer};
+use crate::symbols::owner::Owner;
+use crate::symbols::stored_directory::{StorageDirection, StoredDirectory};
+use crate::symbols::systemd::reload::ReloadService;
+use crate::symbols::systemd::user_service::UserService;
+use crate::symbols::tls::SelfSignedTlsCert;
+use crate::symbols::{Symbol, SymbolRunner};
 
 pub trait Policy {
   fn user_name_for_host(&self, host_name: &'static str) -> String {
diff --git a/src/symbols/file.rs b/src/symbols/file.rs
index ca773a5..f6df2c0 100644
--- a/src/symbols/file.rs
+++ b/src/symbols/file.rs
@@ -6,8 +6,8 @@ use std::io::{Read, Write};
 
 use std::path::Path;
 
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct File<C: AsRef<str>, D: AsRef<Path>> {
   path: D,
@@ -66,7 +66,7 @@ impl<C: AsRef<str>, D: AsRef<Path>> Symbol for File<C, D> {
 }
 
 impl<C: AsRef<str>, D: AsRef<Path>> fmt::Display for File<C, D> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "File {}", self.path.as_ref().display())
   }
 }
diff --git a/src/symbols/git/checkout.rs b/src/symbols/git/checkout.rs
index 88b26b7..27da3b6 100644
--- a/src/symbols/git/checkout.rs
+++ b/src/symbols/git/checkout.rs
@@ -5,9 +5,9 @@ use std::fs::metadata;
 use std::io;
 use std::path::Path;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct GitCheckout<'a, C: CommandRunner, T: AsRef<Path>> {
   target: T,
@@ -28,7 +28,7 @@ impl<'a, C: CommandRunner, T: AsRef<Path>> GitCheckout<'a, C, T> {
 }
 
 impl<'a, C: CommandRunner, T: AsRef<Path>> fmt::Display for GitCheckout<'a, C, T> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(
       f,
       "Checkout {} (branch {}) into {}",
diff --git a/src/symbols/git/submodules.rs b/src/symbols/git/submodules.rs
index 81dcad8..bc00db1 100644
--- a/src/symbols/git/submodules.rs
+++ b/src/symbols/git/submodules.rs
@@ -3,8 +3,8 @@ use std::ffi::OsStr;
 use std::fmt;
 use std::path::Path;
 
-use command_runner::CommandRunner;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct GitSubmodules<'a, P: AsRef<Path>, C: CommandRunner> {
   target: P,
@@ -21,7 +21,7 @@ impl<'a, P: AsRef<Path>, C: CommandRunner> GitSubmodules<'a, P, C> {
 }
 
 impl<'a, P: AsRef<Path>, C: CommandRunner> fmt::Display for GitSubmodules<'a, P, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "Submodules for {}", self.target.as_ref().display())
   }
 }
diff --git a/src/symbols/hook.rs b/src/symbols/hook.rs
index 3ab2660..3cd4519 100644
--- a/src/symbols/hook.rs
+++ b/src/symbols/hook.rs
@@ -1,8 +1,8 @@
 use std::error::Error;
 use std::fmt;
 
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct Hook<A, B>
 where
@@ -83,7 +83,7 @@ where
   A: Symbol,
   B: Symbol,
 {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "Hook {} and then {}", self.a, self.b)
   }
 }
@@ -93,8 +93,8 @@ mod test {
   use std::error::Error;
   use std::fmt;
 
-  use symbols::hook::Hook;
-  use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+  use crate::symbols::hook::Hook;
+  use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
   struct ErrSymbol(String);
   impl Symbol for ErrSymbol {
@@ -116,7 +116,7 @@ mod test {
     }
   }
   impl fmt::Display for ErrSymbol {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
       write!(f, "")
     }
   }
@@ -141,7 +141,7 @@ mod test {
     }
   }
   impl fmt::Display for OkSymbol {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
       write!(f, "")
     }
   }
diff --git a/src/symbols/list.rs b/src/symbols/list.rs
index d9d809c..37d291b 100644
--- a/src/symbols/list.rs
+++ b/src/symbols/list.rs
@@ -1,8 +1,8 @@
 use std::error::Error;
 use std::fmt;
 
-use resources::Resource;
-use symbols::{Action, Symbol, SymbolRunner};
+use crate::resources::Resource;
+use crate::symbols::{Action, Symbol, SymbolRunner};
 
 pub struct List<'a> {
   symbols: Vec<Box<dyn Symbol + 'a>>,
@@ -128,7 +128,7 @@ impl<'a> Action for ListAction<'a> {
 }
 
 impl<'a> fmt::Display for List<'a> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "List [ ")?;
     for symbol in &self.symbols {
       write!(f, "{} ", symbol)?;
diff --git a/src/symbols/mariadb/database.rs b/src/symbols/mariadb/database.rs
index 8861adf..ec7da66 100644
--- a/src/symbols/mariadb/database.rs
+++ b/src/symbols/mariadb/database.rs
@@ -2,8 +2,8 @@ use std::error::Error;
 use std::fmt;
 use std::path::Path;
 
-use command_runner::CommandRunner;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct MariaDBDatabase<'a, D: AsRef<str>, S: AsRef<Path>, C: CommandRunner> {
   db_name: D,
@@ -31,7 +31,7 @@ impl<'a, D: AsRef<str>, S: AsRef<Path>, C: CommandRunner> MariaDBDatabase<'a, D,
 impl<'a, D: AsRef<str>, S: AsRef<Path>, C: CommandRunner> fmt::Display
   for MariaDBDatabase<'a, D, S, C>
 {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "MariaDB Database {}", self.db_name.as_ref())
   }
 }
diff --git a/src/symbols/mariadb/database_dump.rs b/src/symbols/mariadb/database_dump.rs
index 64d3f22..8d0dd2f 100644
--- a/src/symbols/mariadb/database_dump.rs
+++ b/src/symbols/mariadb/database_dump.rs
@@ -2,9 +2,9 @@ use std::error::Error;
 use std::fmt;
 use std::str::FromStr;
 
-use command_runner::CommandRunner;
-use storage::Storage;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::storage::Storage;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct DatabaseDump<'a, N: AsRef<str>, C: CommandRunner, S: Storage> {
   db_name: N,
@@ -30,7 +30,7 @@ impl<'a, N: AsRef<str>, C: CommandRunner, S: Storage> DatabaseDump<'a, N, C, S>
 }
 
 impl<'a, N: AsRef<str>, C: CommandRunner, S: Storage> fmt::Display for DatabaseDump<'a, N, C, S> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "Dump MariaDB Database {}", self.db_name.as_ref())
   }
 }
diff --git a/src/symbols/mariadb/user.rs b/src/symbols/mariadb/user.rs
index 9a6d4e0..ee0df12 100644
--- a/src/symbols/mariadb/user.rs
+++ b/src/symbols/mariadb/user.rs
@@ -1,9 +1,9 @@
 use std::error::Error;
 use std::fmt;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct MariaDBUser<'a, U: AsRef<str>, C: CommandRunner> {
   user_name: U,
@@ -27,7 +27,7 @@ impl<'a, U: AsRef<str>, C: CommandRunner> MariaDBUser<'a, U, C> {
 }
 
 impl<'a, U: AsRef<str>, C: CommandRunner> fmt::Display for MariaDBUser<'a, U, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "MariaDB User {}", self.user_name.as_ref())
   }
 }
diff --git a/src/symbols/mod.rs b/src/symbols/mod.rs
index 20277c0..57f061b 100644
--- a/src/symbols/mod.rs
+++ b/src/symbols/mod.rs
@@ -1,4 +1,4 @@
-use resources::Resource;
+use crate::resources::Resource;
 use std::error::Error;
 use std::fmt::Display;
 
@@ -33,7 +33,7 @@ pub trait Symbol: Display {
 }
 
 // SymbolAction
-pub struct SymbolAction<'a, S: Symbol + 'a> {
+pub struct SymbolAction<'a, S: Symbol> {
   runner: &'a dyn SymbolRunner,
   symbol: &'a S,
 }
diff --git a/src/symbols/nginx/server.rs b/src/symbols/nginx/server.rs
index a4344ea..5d37cb1 100644
--- a/src/symbols/nginx/server.rs
+++ b/src/symbols/nginx/server.rs
@@ -3,10 +3,10 @@ use std::fmt;
 use std::io;
 use std::path::{Path, PathBuf};
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::file::File as FileSymbol;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::file::File as FileSymbol;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 #[derive(Debug)]
 pub enum NginxServerError<E: Error> {
@@ -36,7 +36,7 @@ impl<E: Error> Error for NginxServerError<E> {
 }
 
 impl<E: Error> fmt::Display for NginxServerError<E> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "{}", self.description())
   }
 }
@@ -242,7 +242,7 @@ impl<'a, C: CommandRunner, T: AsRef<str>, P: AsRef<Path>> Symbol for NginxServer
 impl<'a, C: CommandRunner, T: AsRef<str>, P: AsRef<Path>> fmt::Display
   for NginxServer<'a, C, T, P>
 {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "Nginx server config")
   }
 }
diff --git a/src/symbols/noop.rs b/src/symbols/noop.rs
index 2f21443..32943d5 100644
--- a/src/symbols/noop.rs
+++ b/src/symbols/noop.rs
@@ -1,7 +1,7 @@
 use std::error::Error;
 use std::fmt::{self, Display};
 
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct NoopSymbol;
 
@@ -25,7 +25,7 @@ impl Symbol for NoopSymbol {
 }
 
 impl Display for NoopSymbol {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "Noop")
   }
 }
diff --git a/src/symbols/npm.rs b/src/symbols/npm.rs
index 0cfa3e4..6df5a02 100644
--- a/src/symbols/npm.rs
+++ b/src/symbols/npm.rs
@@ -2,8 +2,8 @@ use std::error::Error;
 use std::fmt;
 use std::path::Path;
 
-use command_runner::CommandRunner;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct NpmInstall<'a, T: AsRef<Path>, C: CommandRunner> {
   target: T,
@@ -20,7 +20,7 @@ impl<'a, T: AsRef<Path>, C: CommandRunner> NpmInstall<'a, T, C> {
 }
 
 impl<'a, T: AsRef<Path>, C: CommandRunner> fmt::Display for NpmInstall<'a, T, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(
       f,
       "npm install in {}",
diff --git a/src/symbols/owner.rs b/src/symbols/owner.rs
index 42892c7..0b2e529 100644
--- a/src/symbols/owner.rs
+++ b/src/symbols/owner.rs
@@ -7,9 +7,9 @@ use std::path::Path;
 
 use users::get_user_by_name;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct Owner<'a, C: CommandRunner, D: AsRef<Path>, U: AsRef<str>> {
   path: D,
@@ -61,7 +61,7 @@ impl<'a, C: CommandRunner, D: AsRef<Path>, U: AsRef<str>> Symbol for Owner<'a, C
 }
 
 impl<'a, C: CommandRunner, D: AsRef<Path>, U: AsRef<str>> fmt::Display for Owner<'a, C, D, U> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(
       f,
       "Owner {} for {}",
diff --git a/src/symbols/postgresql/database.rs b/src/symbols/postgresql/database.rs
index 57e6653..d41a43b 100644
--- a/src/symbols/postgresql/database.rs
+++ b/src/symbols/postgresql/database.rs
@@ -1,8 +1,8 @@
 use std::error::Error;
 use std::fmt;
 
-use command_runner::CommandRunner;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct PostgreSQLDatabase<'a, N: AsRef<str>, S: AsRef<str>, C: CommandRunner> {
   name: N,
@@ -31,7 +31,7 @@ impl<'a, N: AsRef<str>, S: AsRef<str>, C: CommandRunner> PostgreSQLDatabase<'a,
 impl<'a, N: AsRef<str>, S: AsRef<str>, C: CommandRunner> fmt::Display
   for PostgreSQLDatabase<'a, N, S, C>
 {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "PostgreSQL Database {}", self.name.as_ref())
   }
 }
diff --git a/src/symbols/postgresql/database_dump.rs b/src/symbols/postgresql/database_dump.rs
index 64d3f22..8d0dd2f 100644
--- a/src/symbols/postgresql/database_dump.rs
+++ b/src/symbols/postgresql/database_dump.rs
@@ -2,9 +2,9 @@ use std::error::Error;
 use std::fmt;
 use std::str::FromStr;
 
-use command_runner::CommandRunner;
-use storage::Storage;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::storage::Storage;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct DatabaseDump<'a, N: AsRef<str>, C: CommandRunner, S: Storage> {
   db_name: N,
@@ -30,7 +30,7 @@ impl<'a, N: AsRef<str>, C: CommandRunner, S: Storage> DatabaseDump<'a, N, C, S>
 }
 
 impl<'a, N: AsRef<str>, C: CommandRunner, S: Storage> fmt::Display for DatabaseDump<'a, N, C, S> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "Dump MariaDB Database {}", self.db_name.as_ref())
   }
 }
diff --git a/src/symbols/stored_directory.rs b/src/symbols/stored_directory.rs
index 9ad5d18..e31ba04 100644
--- a/src/symbols/stored_directory.rs
+++ b/src/symbols/stored_directory.rs
@@ -5,10 +5,10 @@ use std::io;
 use std::path::Path;
 use std::str::FromStr;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use storage::Storage;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::storage::Storage;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 #[derive(Debug, PartialEq)]
 pub enum StorageDirection {
@@ -37,7 +37,7 @@ impl<'a, P: AsRef<Path>, S: Storage, C: CommandRunner> StoredDirectory<'a, P, S,
 impl<'a, P: AsRef<Path>, S: Storage, C: CommandRunner> fmt::Display
   for StoredDirectory<'a, P, S, C>
 {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(
       f,
       "Stored directory {} ({:?})",
diff --git a/src/symbols/systemd/reload.rs b/src/symbols/systemd/reload.rs
index 650ab94..7681ddd 100644
--- a/src/symbols/systemd/reload.rs
+++ b/src/symbols/systemd/reload.rs
@@ -1,10 +1,10 @@
 use std::error::Error;
 use std::fmt;
 
-use command_runner::CommandRunner;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
-pub struct ReloadService<'a, C: 'a + CommandRunner> {
+pub struct ReloadService<'a, C: CommandRunner> {
   service: &'a str,
   command_runner: &'a C,
 }
@@ -42,7 +42,7 @@ impl<'a, C: CommandRunner> Symbol for ReloadService<'a, C> {
 }
 
 impl<'a, C: CommandRunner> fmt::Display for ReloadService<'a, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "Reload service {}", self.service)
   }
 }
diff --git a/src/symbols/systemd/user_service.rs b/src/symbols/systemd/user_service.rs
index a169153..253d404 100644
--- a/src/symbols/systemd/user_service.rs
+++ b/src/symbols/systemd/user_service.rs
@@ -9,10 +9,10 @@ use std::process::Output;
 use std::thread::sleep;
 use std::time::Duration;
 
-use command_runner::{CommandRunner, SetuidCommandRunner};
-use resources::Resource;
-use symbols::file::File as FileSymbol;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::{CommandRunner, SetuidCommandRunner};
+use crate::resources::Resource;
+use crate::symbols::file::File as FileSymbol;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 #[derive(Debug)]
 pub enum UserServiceError<E: Error> {
@@ -44,7 +44,7 @@ impl<E: Error> Error for UserServiceError<E> {
 }
 
 impl<E: Error> fmt::Display for UserServiceError<E> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "{}", self.description())?;
     if let UserServiceError::ActivationFailed(Ok(ref log)) = self {
       write!(f, ": {:?}", log)?;
@@ -222,7 +222,7 @@ impl<'a, C: AsRef<str>, R: CommandRunner> Symbol for UserService<'a, C, R> {
 }
 
 impl<'a, C: AsRef<str>, R: CommandRunner> fmt::Display for UserService<'a, C, R> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "Systemd user service unit for {}", self.service_name)
   }
 }
diff --git a/src/symbols/systemd/user_session.rs b/src/symbols/systemd/user_session.rs
index 602403d..e2dafc6 100644
--- a/src/symbols/systemd/user_session.rs
+++ b/src/symbols/systemd/user_session.rs
@@ -2,8 +2,8 @@ use std::error::Error;
 use std::fmt;
 use std::path::PathBuf;
 
-use command_runner::CommandRunner;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 #[derive(Debug)]
 pub enum SystemdUserSessionError<E: Error> {
@@ -27,7 +27,7 @@ impl<E: Error> Error for SystemdUserSessionError<E> {
 }
 
 impl<E: Error> fmt::Display for SystemdUserSessionError<E> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "{}", self.description())
   }
 }
@@ -73,7 +73,7 @@ impl<'a, U: AsRef<str>, C: CommandRunner> Symbol for SystemdUserSession<'a, U, C
 }
 
 impl<'a, U: AsRef<str>, C: CommandRunner> fmt::Display for SystemdUserSession<'a, U, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "Systemd user session for {}", self.user_name.as_ref())
   }
 }
diff --git a/src/symbols/tls/csr.rs b/src/symbols/tls/csr.rs
index de9681c..5e9e383 100644
--- a/src/symbols/tls/csr.rs
+++ b/src/symbols/tls/csr.rs
@@ -4,11 +4,11 @@ use std::ffi::OsStr;
 use std::fmt;
 use std::path::PathBuf;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
-pub struct TlsCsr<'a, C: 'a + CommandRunner> {
+pub struct TlsCsr<'a, C: CommandRunner> {
   domain: Cow<'a, str>,
   command_runner: &'a C,
 }
@@ -31,7 +31,7 @@ impl<'a, C: CommandRunner> TlsCsr<'a, C> {
 }
 
 impl<'a, C: CommandRunner> fmt::Display for TlsCsr<'a, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "TlsCsr {}", self.domain)
   }
 }
diff --git a/src/symbols/tls/key.rs b/src/symbols/tls/key.rs
index f25c754..9a9fad1 100644
--- a/src/symbols/tls/key.rs
+++ b/src/symbols/tls/key.rs
@@ -4,10 +4,10 @@ use std::ffi::OsStr;
 use std::fmt;
 use std::path::PathBuf;
 
-use command_runner::CommandRunner;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
-pub struct TlsKey<'a, C: 'a + CommandRunner> {
+pub struct TlsKey<'a, C: CommandRunner> {
   domain: Cow<'a, str>,
   command_runner: &'a C,
 }
@@ -32,7 +32,7 @@ impl<'a, C: CommandRunner> TlsKey<'a, C> {
 }
 
 impl<'a, C: CommandRunner> fmt::Display for TlsKey<'a, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "TlsKey {}", self.domain)
   }
 }
diff --git a/src/symbols/tls/self_signed_cert.rs b/src/symbols/tls/self_signed_cert.rs
index 059c154..7724330 100644
--- a/src/symbols/tls/self_signed_cert.rs
+++ b/src/symbols/tls/self_signed_cert.rs
@@ -2,9 +2,9 @@ use std::error::Error;
 use std::fmt;
 use std::path::PathBuf;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct SelfSignedTlsCert<'a, D: AsRef<str>, C: CommandRunner> {
   domain: D,
@@ -29,7 +29,7 @@ impl<'a, D: AsRef<str>, C: CommandRunner> SelfSignedTlsCert<'a, D, C> {
 }
 
 impl<'a, D: AsRef<str>, C: CommandRunner> fmt::Display for SelfSignedTlsCert<'a, D, C> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "SelfSignedTlsCert {}", self.domain.as_ref())
   }
 }
diff --git a/src/symbols/user.rs b/src/symbols/user.rs
index 4b29501..3448a74 100644
--- a/src/symbols/user.rs
+++ b/src/symbols/user.rs
@@ -2,9 +2,9 @@ use std::borrow::Cow;
 use std::error::Error;
 use std::fmt;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 #[derive(Debug)]
 pub enum UserAdderError {
@@ -30,7 +30,7 @@ impl Error for UserAdderError {
 }
 
 impl fmt::Display for UserAdderError {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     match self.cause() {
       Some(e) => write!(f, "{} (cause: {})", self.description(), e),
       None => write!(f, "{}", self.description()),
@@ -61,7 +61,7 @@ impl Error for UserError {
 }
 
 impl fmt::Display for UserError {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     match self.cause() {
       Some(e) => write!(f, "{} (cause: {})", self.description(), e),
       None => write!(f, "{}", self.description()),
@@ -86,7 +86,7 @@ impl<'a, C: CommandRunner, A: 'a + UserAdder> User<'a, C, A> {
 }
 
 impl<'a, C: CommandRunner, A: 'a + UserAdder> fmt::Display for User<'a, C, A> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     write!(f, "User {}", self.user_name)
   }
 }
@@ -126,7 +126,7 @@ impl<'a, C: CommandRunner, A: 'a + UserAdder> Symbol for User<'a, C, A> {
   }
 }
 
-pub struct SystemUserAdder<'a, C: 'a + CommandRunner> {
+pub struct SystemUserAdder<'a, C: CommandRunner> {
   command_runner: &'a C,
 }
 
@@ -171,11 +171,11 @@ mod test {
   use std::error::Error;
   use std::fmt;
 
-  use command_runner::StdCommandRunner;
-  use symbols::user::User;
-  use symbols::user::UserAdder;
-  use symbols::user::UserAdderError;
-  use symbols::Symbol;
+  use crate::command_runner::StdCommandRunner;
+  use crate::symbols::user::User;
+  use crate::symbols::user::UserAdder;
+  use crate::symbols::user::UserAdderError;
+  use crate::symbols::Symbol;
 
   #[derive(Debug, PartialEq)]
   struct DummyError;
@@ -186,7 +186,7 @@ mod test {
   }
 
   impl fmt::Display for DummyError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
       write!(f, "DummyError")
     }
   }
diff --git a/src/symbols/wordpress/plugin.rs b/src/symbols/wordpress/plugin.rs
index 23230c0..7a17deb 100644
--- a/src/symbols/wordpress/plugin.rs
+++ b/src/symbols/wordpress/plugin.rs
@@ -6,9 +6,9 @@ use std::io;
 use std::io::{BufRead, BufReader};
 use std::path::{Path, PathBuf};
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct WordpressPlugin<'a, P: AsRef<Path>, N: AsRef<str>, R: CommandRunner> {
   base: P,
@@ -122,7 +122,7 @@ impl<'a, P: AsRef<Path>, N: AsRef<str>, R: CommandRunner> Symbol for WordpressPl
 impl<'a, P: AsRef<Path>, N: AsRef<str>, R: CommandRunner> fmt::Display
   for WordpressPlugin<'a, P, N, R>
 {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "WordpressPlugin {}", self.name.as_ref())
   }
 }
diff --git a/src/symbols/wordpress/translation.rs b/src/symbols/wordpress/translation.rs
index 469406d..9876be7 100644
--- a/src/symbols/wordpress/translation.rs
+++ b/src/symbols/wordpress/translation.rs
@@ -9,9 +9,9 @@ use std::io::{BufRead, BufReader};
 use std::path::Path;
 use std::path::PathBuf;
 
-use command_runner::CommandRunner;
-use resources::Resource;
-use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
+use crate::command_runner::CommandRunner;
+use crate::resources::Resource;
+use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
 
 pub struct WordpressTranslation<'a, C: AsRef<str>, D: AsRef<Path>, R: CommandRunner> {
   path: D,
@@ -139,7 +139,7 @@ impl<'a, C: AsRef<str>, D: AsRef<Path>, R: CommandRunner> Symbol
 impl<'a, C: AsRef<str>, D: AsRef<Path>, R: CommandRunner> fmt::Display
   for WordpressTranslation<'a, C, D, R>
 {
-  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
     write!(f, "WordpressTranslation {}", self.path.as_ref().display())
   }
 }
diff --git a/tests/file.rs b/tests/file.rs
index 6fe6d4f..d11172c 100644
--- a/tests/file.rs
+++ b/tests/file.rs
@@ -1,6 +1,3 @@
-extern crate schematics;
-extern crate tempdir;
-
 use schematics::symbols::file::File as FileSymbol;
 use schematics::symbols::Symbol;
 use std::fs::File;
diff --git a/tests/storage.rs b/tests/storage.rs
index 2396f55..964c3c5 100644
--- a/tests/storage.rs
+++ b/tests/storage.rs
@@ -1,7 +1,3 @@
-extern crate regex;
-extern crate schematics;
-extern crate tempdir;
-
 use regex::Regex;
 use schematics::storage::{SimpleStorage, Storage};
 use std::fs::{create_dir, File};