Admin roles

Since you're not using this controller, it shouldn't be committed.  (You only want to commit and push files that you're using, otherwise you end up with lots of unnecessary files/code.)

However, I think you should have at least `index` and `destroy` actions for reviews.  A good admin function would be to have a page that lists all of the reviews, with a "Delete" button next to each.  That way an admin can easily scan for inappropriate reviews and remove them.  I'd add a test that says an admin can view a list of all reviews and one that says an admin can delete a review, and use those to test drive those actions.