You've already forked prometheus-fail2ban-exporter
Add a basic systemd service file to serve as an example on how to run the exporter as a system service. Add short README with an overview of the service file.
Systemd
The .service file in this directory is to be put into /etc/systemd/system.
It expects the binary file to be installed at /usr/sbin/fail2ban_exporter.
It expects a user named fail2ban_exporter to exist.
This user should not have a shell or any special privileges aside from read-access to the fail2ban socket file.
The ExecStart line can be modified to add any custom CLI flags.