The flogic guys have a great write up detailing their setup. They go into detail on how to setup a local mirror to use when deploying your app.
Here’s a summary, in their own words:
Here’s how we’re doing the mirroring… In the discussion that follows there are three machines involved: (1) a local workstation (or laptop, as the case actually is) where I’m doing development work, I’ll refer to it as “local”; (2) a git repository host under our control, which will be running gitosis, to which we push, and which then mirrors to github, called “internal”; and (3) github.com.
Update: I forgot to link to the blog post outside of the image. Thanks Matt.