I do this in the init or upstart script.
I used to use init because it was easy, but I found situations where god would segfault and leave my systems open to failure. So now I use an upstart script with respawn to ensure in the unlikely event that god crashes it is automatically restarted.
These scripts are written for my capistrano deployment so you will have to do some interpolating of the values that capistrano normally provides, but it will give you a roadmap to make it happen.
Hopefully obvious that if you use the upstart script your system needs to have the upstart subsystem. check to see if you already have .conf files in "/etc/init"