* [#10] Users can Register for Contests
* Added the Registration model which will store a User's registration for a Contest
* [#10] Users can Register for Contests
* Initial implementation of User#register without any category checks
* [#10] Users can Register for Contests
* Added category checks
* Added invalid contest checks and associated exception
* Added :dependent => :destroy clauses to all models
* [#10] Users can Register for Contests
* Added withdraw functionality
* [#10] Users can Register for Contests
* Added documentation for the three methods currently in place
* Added yard default options
Merge pull request #25 from sjaveed/mist-10

Users can now register for Contests as well as withdraw their registrations from previously registered Contests