Ratyrate2

This adds ratings. 
2 caveats:
 1) ratings do not show until a refresh. This is something that has been brought up on the ratyrate issues page, but I don't know if it is a bug in ratyrate, or me doing something wrong.
2) I had to comment out some of the rails-generated tests, complaining about authentication. Simplecov still shows 100% (I think some other tests are hitting the same code). In the browser, only a logged in user can rate, so I think we're still good.

Given these caveats - do y'all want to merge? Matt and Chris, I think you both had found some stuff about adding stars, but this was all I could find.