Set up gems and other configuration

Based on the setup instructions found in:
https://github.com/jotiffany/user_maintenance/wiki

The project has been set up with the ff:
- RSpec, Factory Girl, Faker and Populator for testing
- CoffeeScript, SASS, JQuery, HAML and SimpleForm for
front end development
- rubocop for code check
- postgresql for the database

Signed-off-by: Joan Tiffany Siy <joan@teamcodeflux.com>