FYI, perhaps to get you pointed in the right direction...I use a set of scripts to deploy a new server. I don't use exactly these, but here are some scripts that might get you started:
https://github.com/joshfng/railsready
That will more or less get you up and running with Ubuntu, Ruby, Passenger, and Rails.
After the above, or if you already have your servers up and running, I use capistrano to manage application deployments:
https://github.com/capistrano/capistrano/wiki
and some tips to get you started:
http://help.github.com/deploy-with-capistrano/
My deployments run similarly to those you will find there; git repository is cached, copied from there to the deployment directories, and then some custom steps to adjust symlinks, permissions, etc.
Anyway, maybe that will help...