add migration

Author: valentijnscholten

docs/content/en/open_source/upgrading/2.53.md

@@ -31,7 +31,13 @@ The switch to `django-pghistory` provides several advantages:
 ### Migration Notes
 
 - A one-time data migration will take place to populate the `django-pghistory` tables with the initial snapshot of the tracked models.
+- The migration is designed to be fail-safe: if it fails for some reason, it will continue where it left off.
+- The migration can also be performed up front via
+  - `docker compose exec uwsgi bash -c "python manage.py pghistory_backfill_fast"`, or
+  - `docker compose exec uwsgi bash -c "python manage.py pghistory_backfill_simple"`, or
+  - `docker compose exec uwsgi bash -c "python manage.py pghistory_backfill"`
 
+The backfill migration is not mandatory to succeed. If it fails for some reason, the only side effect will be that the first auditlog diff will contain all fields of an object instead just the changed fields.
 ---
 
 Check the [Release Notes](https://github.com/DefectDojo/django-DefectDojo/releases/tag/2.53.0) for the complete contents of this release.