Restart the AuthGroup id sequence on postgres

openslides/users/signals.py

@@ -1,5 +1,6 @@
 from django.apps import apps
 from django.contrib.auth.models import Permission
+from django.db import connection
 from django.db.models import Q
 
 from ..utils.auth import GROUP_ADMIN_PK, GROUP_DEFAULT_PK
@@ -185,3 +186,12 @@ def create_builtin_groups_and_admin(**kwargs):
     # After each group was created, the permissions (many to many fields) where
     # added to the group. But we do not have to update the cache by calling
     # inform_changed_data() because the cache is updated on server start.
+
+    # For postgres, the id sequence (the current auto increment value for the id field)
+    # needs to be refreshed after inserting the groups per id, because postgres does not
+    # increment the sequence then.
+    if connection.vendor == "postgresql":
+        with connection.cursor() as cursor:
+            cursor.execute("SELECT max(id) + 1 as max FROM auth_group;")
+            max_id = cursor.fetchone()[0]
+            cursor.execute(f"ALTER SEQUENCE auth_group_id_seq RESTART WITH {max_id};")