Docs - add 'manage push rules' to permissions table

doc/user/permissions.md

@@ -125,6 +125,7 @@ The following table depicts the various user permission levels in a project.
 | Manage Error Tracking                             |         |            |             | ✓        | ✓      |
 | Delete wiki pages                                 |         |            |             | ✓        | ✓      |
 | View project Audit Events                         |         |            |             | ✓        | ✓      |
+| Manage [push rules](../push_rules/push_rules.md)  |         |            |             | ✓        | ✓      |
 | Switch visibility level                           |         |            |             |          | ✓      |
 | Transfer project to another namespace             |         |            |             |          | ✓      |
 | Remove project                                    |         |            |             |          | ✓      |