Fonts without CDN in a Rails app

gistfile1.rb

config.action_controller.asset_host = proc do |source|
  if source =~ /(ttf|ttc|otf|eot|woff|svg)$/
    "https://www.domain.com"
  else
    "https://cdn#{Digest::MD5.hexdigest(source).to_i(16) % 4 }.domain.com"
  end
end