module ActionController::MimeResponds::ClassMethods

def respond_to(*)
  raise NoMethodError, "The controller-level `respond_to' feature has " \
    "been extracted to the `responders` gem. Add it to your Gemfile to " \
    "continue using this feature:\n" \
    "  gem 'responders', '~> 2.0'\n" \
    "Consult the Rails upgrade guide for details."
end