Added documentation for user/card service methods
Added sinon to models devDependencies
Added unit tests for user module.
Added sinon to models devDependencies
Added unit tests for user module.
Removed bcrypt and uuid from users action as the new User model takes care of this.
Updated validateCredentials step to use method on dbUser property
Removed bcrypt-nodejs dependency from authentication module
Removed bcrypt-nodejs dependency from authentication module