This is a blank Rails application set up with React (Facebook JS lib for building UIs), Sprockets preprocessor for CJSX (CoffeeScript with React JSX markup), and Compass Stylesheet Authoring Framework for cross browser crap
If you don't want to use React add-ons and want to have lightweight lib just comment this line in config/application.rb
config.react.addons = true
Read more about React add-ons here