docs: added new admin trick to bulk change owner of repository

docs/admin/system_admin/admin-tricks.rst

@@ -262,3 +262,39 b' ishell interface should be used.'
   In [1]: repo = Repository.get_by_repo_name('SOME_REPO_NAME')
   In [2]: repo.archived = False
   In [3]: Session().add(repo);Session().commit()
+
+
+
+
+Bulk change repository owner
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Here's how one can change an owner of repository for an user who has been de activated.
+Settings a new owner can be done via ishell for all repositories that past owner had.
+
+do run this script the interactive ishell interface should be used.
+
+.. code-block:: bash
+
+  # Open iShell from the terminal
+  $ rccontrol ishell enterprise-1/community-1
+
+
+.. code-block:: python
+
+    from rhodecode.model.db import User, Repository, Session
+    from rhodecode.model.permission import PermissionModel
+
+    # replace old-owner and new-owner with your exact users
+    old_owner = User.get_by_username('old-owner')
+    new_owner = User.get_by_username('new-owner')
+
+    # list of users we need to "flush" permissions
+    affected_user_ids = [new_owner.user_id, old_owner.user_id]
+
+    for repo in Repository.get_all_repos(user_id=old_owner.user_id):
+        repo.user = new_owner
+        Session().add(repo)
+        Session().commit()
+
+    PermissionModel().trigger_permission_flush(affected_user_ids)