implemented decorator for Video model to move the average_rating_string method to the decorator
created UserCreation service and associated tests, and moved some tests from users controller to services.  Used Mocks to confirm messaging between the controller nad UserCreation service
refactored code to more closely match the solution, which has the user validation also happening in the service, rather than controller
code cleanup prior to code review
Made code changes to reflect code review comments
Merge pull request #13 from yev2000/beyond_mvc

Implemented service for user creation and decorator for video average rating string.
Made some test fixed based on code review comments.