def url
      url_root = self.class.url_root
      raise Error.new("Please specify a url_root for the #{self.class.to_s}") unless url_root

      if url_root.respond_to?(:call)
        url_root = instance_exec(&url_root)
      end

      url_root + "/#{id}"
    end
def url
      url_root = self.class.url_root
      raise Error.new("Please specify a url_root for the #{self.class.to_s}") unless url_root

      if url_root.respond_to?(:call)
        url_root = instance_exec(&url_root)
      end

      url_root + "/#{id}"
    end
Public: The URL of the entity

 Returns a String that is the URL of the entity