Systemd example (lavalink-devs#890)

Co-authored-by: Toπ <[email protected]>
Co-authored-by: Freya Arbjerg <[email protected]>

README.md

@@ -25,6 +25,7 @@ A [basic example bot](Testbot) is available.
 - [Server configuration](#server-configuration)
   - [Config](#config)
   - [Binary](#binary)
+  - [Systemd Serivce](#systemd-service)
   - [Docker](#docker)
 
 </details>
@@ -219,6 +220,48 @@ Put an `application.yml` file in your working directory. ([Example here](Lavalin
 
 Run with `java -jar Lavalink.jar` from the same directory
 
+### Systemd Service
+
+If you're using a Systemd-based Linux distribution you may want to install Lavalink as a background service. You will need to create a `lavalink.service` file inside `/usr/lib/systemd/system`. Create the file with the following template (replacing the values inside the `<>` brackets):
+ ```ini
+[Unit]
+# Describe the service
+Description=Lavalink Service
+
+# Configure service order
+After=syslog.target network.target
+
+[Service]
+# The user which will run Lavalink
+User=<usr>
+
+# The group which will run Lavalink
+Group=<usr>
+
+# Where the program should start
+WorkingDirectory=</home/usr/lavalink>
+
+# The command to start Lavalink
+ExecStart=java -Xmx4G -jar </home/usr/lavalink>/Lavalink.jar
+
+# Restart the service if it crashes
+Restart=on-failure
+
+# Delay each restart by 5s
+RestartSec=5s
+
+[Install]
+# Start this service as part of normal system start-up
+WantedBy=multi-user.target
+```
+
+To initiate the service, run 
+```shell
+sudo systemctl daemon-reload
+sudo systemctl enable lavalink
+sudo systemctl start lavalink
+```
+In addition to the usual log files, you can also view the log with `sudo journalctl -u lavalink`.
 ### Docker
 
 Docker images can be found under [packages](https://github.com/lavalink-devs/Lavalink/pkgs/container/lavalink) with old builds prior to `v3.7.4` being available on [Docker Hub](https://hub.docker.com/r/fredboat/lavalink/).
@@ -258,5 +301,4 @@ networks:
 Run `docker compose up -d`. See [Docker Compose Up](https://docs.docker.com/engine/reference/commandline/compose_up/)
 
 If your bot also runs in a docker container you can make that container join the lavalink network and use `lavalink` (service name) as the hostname to connect.
-See [Docker Networking](https://docs.docker.com/network/) & [Docker Compose Networking](https://docs.docker.com/compose/networking/)
-
+See [Docker Networking](https://docs.docker.com/network/) & [Docker Compose Networking](https://docs.docker.com/compose/networking/)