fix: Try to fix the group and permission creation

src/fellchensammlung/apps.py

@@ -2,9 +2,15 @@ from django.apps import AppConfig
 from .tools.signals import ensure_groups
 from django.db.models.signals import post_migrate
 
+
+
 class FellchensammlungConfig(AppConfig):
     default_auto_field = 'django.db.models.BigAutoField'
     name = 'fellchensammlung'
 
     def ready(self):
-        post_migrate.connect(ensure_groups, sender=self)
+        from django.contrib.auth.models import Permission
+        try:
+            post_migrate.connect(ensure_groups, sender=self)
+        except Permission.DoesNotExist:
+            pass