updates last_update on each save

sync/models/base.py

@@ -11,7 +11,7 @@ logger = logging.getLogger(__name__)
 
 class BaseModel(models.Model):
     creation_date = models.DateTimeField(default=now, editable=False)
-    last_update = models.DateTimeField(default=now)
+    last_update = models.DateTimeField(auto_now=True)
     related_user = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.SET_NULL, related_name='+')
     last_updated_by = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.SET_NULL, related_name='+')
     data_access_ids = models.JSONField(default=list)