module RetinaJs
  class Engine < ::Rails::Engine
  end
end

module ImageHelper
  def image_tag_with_at2x(name_at_1x, options={})
    name_at_2x = name_at_1x.gsub(%r{\.\w+$}, '@2x\0')
    image_tag(name_at_1x, options.merge("data-at2x" => asset_path(name_at_2x)))
  end
end
ActionView::Base.send :include, ImageHelper