Fixed route issues with Invitations and Feedback Controllers tests
Several enhancements in brails tests

Added macro for login
Added Roles for user models, using a fork of the mongoid-roles gem that is compatible with mongoid-4 and bson-2 gems
Added Users controllers tests
Refactored tests

Moved Commentable shared specs to spec/support folder
Changed achievement relationship from user to profile model
Added let method for defining variables in several test specs
Removed #answer specs from Question model specs
Changed feedback and invitations email validations to devise email regexp validator. Added basic tests for download of audio file in content controller spec