And add support for additional query parameters:
- `author_id`: Returns merge requests created by the given user `id`
- `assignee_id`: Returns merge requests assigned to the given user `id`
- `scope`: Return merge requests for the given scope: `created-by-me`, `assigned-to-me` or `all`
counter
This is done by:
- Extending the IssuableFinder adding the non_archived option to the params
- Overriding the #filter_params in the MergeRequestsAction
- Passing the non_archived param in the nav/_group.html.haml navbar
partial from the groups/merge_requests.html.haml
