Setup testing

Sets up:
- [x] pry-rails
- [x] rspec-rails
- [x] capybara
- [x] selenium-webdriver
- [x] capybara-webkit
- [x] capybara-screenshot
- [x] factory_girl_rails
- [x] database_cleaner
- [x] shoulda-matchers
- [x] better_errors
- [x] binding_of_caller
- [x] meta_request

Other:
- [x] foreman
- [x] puma
- [x] draper
- [x] slim_rails