How to autodetect model id in django?

Question

Django

There is a regular model in django

class Catalog(modles.Model):
  name_category = models.CharField('название категории', max_length=40)
  id_category = PositiveIntegerField()

id_category - This is the id of the created category, you need to make sure that this id calculates itself.
That is, I made the first category, id was assigned to it - 1
, created the second category - id 2 , the
third - id 3
, and so on according to the algorithm.
I promise feedback, thanks in advance for your help.