Create macros

[yordis]

  defmacro payload_object(payload_name, result_object_name) do
    quote location: :keep do

      object unquote(payload_name) do
        field :successful, non_null(:boolean), description: "Indicates if the mutation completed successfully or not. "
        field :messages, list_of(:validation_message), description: "A list of failed validations. May be blank or null if mutation succeeded."
        field :result, unquote(result_object_name), description: "The object created/updated/deleted by the mutation. May be null if mutation failed."
      end
    end
  end