How do I export the revision history of a gdoc to git?

I have a spreadsheet in google docs that I'd want to integrate in a git workflow (and push to github). Are there any tools (or even libraries that are gdoc version aware) that do, or help me do, that?

I have some old ruby hacks lying around based on the google_spreadsheet gem that reads and writes current versions of a csv gdoc, but nothing which extracts revision history.