code: func (c *Controller) Todo() Result {
  	c.Response.Status = http.StatusNotImplemented
  	controllerLog.Debug("Todo: Not implemented function", "action", c.Action)
  	return c.RenderError(&Error{
  		Title:       "TODO",
  		Description: "This action is not implemented",
  	})
  }
docs: // Todo returns an HTTP 501 Not Implemented "todo" indicating that the
  // action isn't done yet.