Rails : Server separate images in production and development environment

application_helper.rb

module ApplicationHelper
  # It hijacks the methods

  [:image_tag, :image_path, :image_url].each do |m_name|
    define_method(m_name) do |*arg|
      begin
        super(*arg)
      rescue Sprockets::Rails::Helper::AssetNotFound
        arg[0] = "#{Rails.env}/#{arg[0]}"
        super(*arg)
      end
    end
  end
end