Second merge from Development to Master branch 

- Updated Peep and User classes
- Created tests to allow User to sign-up, sign-in, and sign-out
- Created Rakefile
- Updated Gemfile with information on new gems
- Updated views and .erb files based on new page structure
- Refactored code and moved helper and views directories and chitter.rb and data_mapper_setup.rb files into a new app directory