AppHarbor is pretty neat, but unlike Heroku, I can't figure out how it works. Are there any open source implementations? From my searching I could not find any.
My crude implementations so far have been setting up a git server and on each new repo, spin up an instance of IIS. This sort of works, but I can't figure out how "add-ons" get configured to a paticular instance.
I guess, to narrow my question down, is I'm looking if there are any open source implementations of "git based deployment" for Windows, or a general architectural overview of how this would best best accomplished.