Fix sql migration

aleksis/core/migrations/0046_add_room_model.py

@@ -47,8 +47,7 @@ class Migration(migrations.Migration):
         migrations.RunSQL(
             """
             -- Use a temporary, empty source table in case Chronos is not installed
-            CREATE TEMPORARY TABLE IF NOT EXISTS chronos_room (LIKE core_room);
-            INSERT INTO core_room SELECT * FROM chronos_room;
+            DO $$BEGIN INSERT INTO core_room SELECT * FROM chronos_room; EXCEPTION WHEN undefined_table THEN NULL; END$$;
             """
         ),
     ]