Rails 4, much to everyone's annoyance, provides no option to generate both digest and non-digest assets. Installing this gem automatically creates both digest and non-digest assets which are useful for many reasons. See this issue for more details: https://github.com/rails/sprockets-rails/issues/49
Gemfile gem 'non-stupid-digest-assets', '~> 1.0.4'
install gem install non-stupid-digest-assets