Just a quick git refresher from gitimmersion.com, did not go as deep as I had wished nor did it provide advanced git stuff.
50 or so quick lessons from gitimmersion.com
Helped a little bit with reset/revert/rebase/merge etc. since sometimes things become wonky.
Did not help with huge multiple users and how to deal with that, but it seems it's always a case by case basis anyway.
Did this in python instead of ruby.