Rails: using url helpers inside custom class.

url_helpers.rb

module UrlHelpers
  extend ActiveSupport::Concern

  def default_url_options
    Rails.configuration.action_mailer.default_url_options
  end

  included do
    include Rails.application.routes.url_helpers
  end
end

class MyClass
  include UrlHelpers
end  

MyClass.new.instance_eval { root_url }
=> "http://localhost:3000/"

MyClass.new.instance_eval { registration_url }
 => "http://localhost:3000/registration"