Continue refactoring. Add site model and mapper. Moved a few more methods out of database class.
Add tests for mappers persist methods. Refactor app.rb to use models in conjunction with mappers.
Add validations to models. Add mapper specs. Refactor user_mapper#persist to catch duplicate key errors. Add unique index on user.email. Remove method to check email already taken.
Refactor sign-up post to handle all validations and persist
Merge pull request #23 from DevanB/mappers

Continue refactoring.