Notfellchen/src/fellchensammlung/apps.py

from django.apps import AppConfig
from .tools.signals import ensure_groups, ensure_languages
from django.db.models.signals import post_migrate



class FellchensammlungConfig(AppConfig):
    default_auto_field = 'django.db.models.BigAutoField'
    name = 'fellchensammlung'

    def ready(self):
        from django.contrib.auth.models import Permission
        try:
            post_migrate.connect(ensure_groups, sender=self)
        except Permission.DoesNotExist:
            pass
        post_migrate.connect(ensure_languages, sender=self)