Add systemd unit file

README.md

@@ -82,7 +82,15 @@ screen
 ./server.rb
 ```
 
-A systemd unit file will be added at some point so it starts automatically on boot.
+Alternatively, you can use the provided systemd unit file. The instructions below will start it immediately, and then automatically on reboot. You'll need to be root to do these steps:
+
+```
+cp systemd/octolux_server.service /etc/systemd/system
+systemctl start octolux_server.service
+systemctl enable octolux_server.service
+```
+
+The logs can then be seen with `journalctl -u octolux_server.service`.
 
 ### octolux.rb
 

systemd/octolux_server.service

@@ -0,0 +1,12 @@
+[Unit]
+Description=Octolux Server
+
+[Service]
+User=pi
+Restart=always
+RestartSec=5
+WorkingDirectory=/home/pi/octolux
+ExecStart=/home/pi/octolux/server.rb
+
+[Install]
+WantedBy=default.target