snf_django: Associate two more apps with Astakos

The apps "quotaholder_app" and "auth" have models that are stored in the
Astakos database, and should thus be included in the check of
`select_db()`.

snf-django-lib/snf_django/utils/db.py

@@ -32,7 +32,8 @@ def select_db(app):
     if not routers or SYNNEFO_ROUTER not in settings.DATABASE_ROUTERS:
         return "default"
 
-    if app == "im" and ASTAKOS_DATABASE in settings.DATABASES:
+    if (app in ["im", "auth", "quotaholder_app"] and
+            ASTAKOS_DATABASE in settings.DATABASES):
         return ASTAKOS_DATABASE
     elif app == "db" and CYCLADES_DATABASE in settings.DATABASES:
         return CYCLADES_DATABASE