class Sprockets::Rails::Helper::AssetNotPrecompiledError

def initialize(source)
  msg =
  if using_sprockets4?
    "Asset `#{ source }` was not declared to be precompiled in production.\n" +
    "Declare links to your assets in `app/assets/config/manifest.js`.\n\n" +
    "  //= link #{ source }\n\n" +
    "and restart your server"
  else
    "Asset was not declared to be precompiled in production.\n" +
    "Add `Rails.application.config.assets.precompile += " +
    "%w( #{source} )` to `config/initializers/assets.rb` and " +
    "restart your server"
  end
  super(msg)
end