@serios I presume you’re meaning the Menu component? If so, you’d need to amend the onRun() method inside /extensions/local/components/Menu.php and assign the appropriate variables to $this->page, either that or amend the with() in the loadList to add your relation.
I’m happy to help, but at this point sharing code would be helpful - probably best to set it up as a GitHub repo so I can contribute more effectively.
@scooby420 if all you want is to quickly add allergens, simply add a column to ti_menus and add the field to admin/models/config/Menus_model.php. It will then be available to output in the front end. Everyone here is working on this in their free time, so its unlikely to be done at the speed you seem to be needing.