Added user authentication for log in log out

I used Devise, it is probably not ideal as it makes a ton of
assumptions, but for this app I wanted to keep it simple and it does
provide everything out of the box for a simple rails app.

I also added two feature tests to make sure I had the routing done
correctly.
Merge pull request #1 from shicholas/allow_user_to_login

Added user authentication for log in log out