Added some tests and inline comments

I added a few specs here to show how you might test some of your existing code more thoroughly.  I also noted that you weren't confirming ownership of the restaurant before updating, so I added tests and logic for that.

There are some inline comments to describe my thought process.  Leave this pull request outstanding for now so the other students can take a look as well.  In this requests, check out the "files changed" tab to see where I made edits.  Hopefully the diff isn't too touch to read ;)