Save UUID of merged user

lastuser_core/models/__init__.py

@@ -58,7 +58,7 @@ def merge_users(user1, user2):
                 for row in model.query.filter_by(user_id=merge_user.id).all():
                     row.user_id = keep_user.id
     # 2. Add merge_user's userid to olduserids. Commit session.
-    db.session.add(UserOldId(user=keep_user, userid=merge_user.userid))
+    db.session.add(UserOldId(user=keep_user, userid=merge_user.userid, uuid=merge_user.uuid))
     # 3. Mark merge_user as merged. Commit session.
     merge_user.status = USER_STATUS.MERGED
     # 4. Release the username