Systemd deploy (#669)

* Added systemd config for deployment

* Add menu option.

* Update docs/deploy/systemd.md

Co-authored-by: Tim Condon <0xTim@users.noreply.github.com>

* Update docs/deploy/systemd.md

Co-authored-by: Tim Condon <0xTim@users.noreply.github.com>

* Update docs/deploy/systemd.md

Co-authored-by: Tim Condon <0xTim@users.noreply.github.com>

* Update docs/deploy/systemd.md

Co-authored-by: Tim Condon <0xTim@users.noreply.github.com>

* Added  stop, restart commands and more details on user to run them as

* Update docs/deploy/systemd.md

* Update docs/deploy/systemd.md

* Update docs/deploy/systemd.md

Co-authored-by: Tim Condon <0xTim@users.noreply.github.com>

docs/deploy/systemd.md

@@ -0,0 +1,68 @@
+# Systemd
+
+Systemd is the default system and service manager on most Linux distributions. It is usually installed by default so no installation is needed on supported Swift distributions.
+
+## Configure
+
+Each Vapor app on your server should have its own service file. For an example `Hello` project, the configuration file would be located at `/etc/systemd/system/hello.service`. This file should look like the following:
+
+```sh
+[Unit]
+Description=Hello
+Requires=network.target
+After=network.target
+
+[Service]
+Type=simple
+User=vapor
+Group=vapor
+Restart=always
+RestartSec=3
+WorkingDirectory=/home/vapor/hello
+ExecStart=/home/vapor/hello/.build/release/Run serve --env production
+StandardOutput=syslog
+StandardError=syslog
+SyslogIdentifier=vapor-hello
+
+[Install]
+WantedBy=multi-user.target
+```
+
+As specified in our configuration file the `Hello` project is located in the home folder for the user `vapor`. Make sure `WorkingDirectory` points to the root directory of your project where the `Package.swift` file is.
+
+The `--env production` flag will disable verbose logging.
+
+### Environment
+Otherwise, quoting the values is optional but recommended.
+
+You can export variables in two ways via systemd. Either by creating an environment file with all the variables set in it:
+
+```sh
+EnvironmentFile=/path/to/environment/file1
+EnvironmentFile=/path/to/environment/file2
+```
+
+
+Or you can add them directly to the service file under `[service]`:
+
+```sh
+Environment="PORT=8123"
+Environment="ANOTHERVALUE=/something/else"
+```
+Exported variables can be used in Vapor using `Environment.get`
+
+```swift
+let port = Environment.get("PORT")
+```
+
+## Start
+
+You can now load, enable, start, stop and restart your app by running the following as root.
+
+```sh
+systemctl daemon-reload
+systemctl enable hello
+systemctl start hello
+systemctl stop hello
+systemctl restart hello
+```

mkdocs.yml

@@ -23,7 +23,7 @@ theme:
   palette:
     primary: black
     accent: blue
-  
+
   logo: assets/logo.png
   favicon: assets/favicon.png
 
@@ -31,10 +31,10 @@ theme:
     - search.suggest
     - search.highlight
 
-# Customization 
+# Customization
 extra:
   # Font
-  font: 
+  font:
     text: Roboto Slab
     code: Source Code Pro
 
@@ -74,14 +74,14 @@ plugins:
       material_alternate: true
       # Add the new languages here. DON'T CHANGE THE DEFAULT LANGUAGE
       languages:
-        en: 
+        en:
           name: English
           build: true
         zh:
           name: 简体中文
           site_name: Vapor 中文文档
           build: true
-        nl: 
+        nl:
           name: Nederlands
           site_name: Vapor Documentatie
           build: true
@@ -97,9 +97,9 @@ plugins:
       nav_translations:
         nl:
           Welcome: Welkom
-        fr: 
+        fr:
           Welcome: Bienvenue
-        de: 
+        de:
           Welcome: Willkommen
         zh:
           Welcome: 序言
@@ -210,6 +210,7 @@ nav:
   - DigitalOcean: "deploy/digital-ocean.md"
   - Heroku: "deploy/heroku.md"
   - Supervisor: "deploy/supervisor.md"
+  - Systemd: "deploy/systemd.md"
   - Nginx: "deploy/nginx.md"
   - Docker: "deploy/docker.md"
 - Version (4.0):