* IMPORTANT: Fixed bad bug. It was not possible to have two fields on the same
model that use the same item type. I had to add a new field to the generic
key model, which is a mandatory field. After updating to this version,
you need to delete all your items and generic FKs and create a datamigration
that iterates over all your objects and saves them, so that the items
get re-created. Unfortunately you will have to approve all items again.