work on adding comments to restaurant show page

Created CommentsController
change restaurant controller (prob was a no no)
Did some other things that simply did not work.  I'm tired. should rest and tackle this in the morning. 
Any good feedback would be welcome. 
I think this `uniqueness` validation will prevent a comment from being created if its `restaurant_id` isn't unique... which means you won't be able to have more than one comment per restaurant. Is that what you intended?