New resource Users
Create new user, edit user data, delete user
Sign In and Sign Out
Updated tests to handle SignIn
Small fix in destroy action
Fixed redirect after updating user data, plus only signed in users can post reviews, and create / update / delete movies
beforeFilter for Movies, Reviews and Users
Fixed test that broke because of beforeFilter
Modified beforeFilter to allow signing up before signing in (!)
Link to profile page, user can only update/delete his own profile
Added link to all users.    Used link_to_route for all links.