Fix production build (#408)
Fix production build (#408)

Per https://github.com/shakacode/react_on_rails/pull/895
justin808/react-webpack-rails-tutorial,justin808/react-webpack-rails-tutorial,shakacode/react-webpack-rails-tutorial,shakacode/react-webpack-rails-tutorial,justin808/react-webpack-rails-tutorial,shakacode/react-webpack-rails-tutorial,justin808/react-webpack-rails-tutorial,shakacode/react-webpack-rails-tutorial