Use systemd instead of /etc/rc.local to start script

[decantr]

The current method of auto starting the setup script is through the rc.local file.

Appending to this before the exit 0 is not recomended as the file states at the top "Make sure that the script will exit 0" which we can ensure will happen if our script fails.

Ideally we would be using a systemd service to run the setup script on startup.
This has the added benefit of allowing the "wait for network" option so it only runs once the interface is up.

[decantr]

Running the command seems to be the way to go about "systemctl enable" without being logged in.
sudo ln -s /etc/systemd/system/rgu-h-setup.service /etc/systemd/system/multi-user.target.wants/rgu-h-setup.service