Assets setup

Add React JS and Foundation. Also specified a Ruby version (for people using rbenv at least, not sure how it exactly works with rvm). Also removed the Coffeescript gem, because I think coffee -> jsx -> javascript would end up being kind of a mess. This hasn't caused any dependency problems for me, but not 100% sure on this one, so just let me know if this messes anything up.

React and Foundation  should "just work" after you install the gems
I'll get it on the pr for the branch I made off this one