Build something that works
'git checkout' is definitely a valuable command, but for the beginning Rails user, I believe that getting into the details of how Git works may confuse more than it helps. My hope is that students will complete the course and go on to learn many of the topics that aren't covered in the videos.
Perhaps a "explore more" list (with links) would help students see the map of what else they should be learning in more detail. It can also act as a map or test for future features, kind of like test specs do for apps. ;)
Yeah, like a resource list - is that what you mean? Oh man, I've run across so many of good blog posts / articles / guides over the past few months - I'm sure I could create a pretty epic list :-)