The DAGs main page has All/Active/Paused.

It would be nice if we can have also Running Now which will show all the DAGs that have at least 1 in Running of DAG runs:
![Screen Shot 2021-08-25 at 11 30 55](https://user-images.githubusercontent.com/62940116/130756490-647dc664-7528-4eb7-b4d8-515577f7e6bb.png)


For the above example the new DAGs tab of Running Now should show only 2 rows.
The use case is to see easily what DAGs are currently in progress.

"""View to show records from Task Reschedule table."""
    route_base = "/triggerview"
    datamodel = AirflowModelView.CustomSQLAInterface(models.Trigger)  
    class_permission_name = permissions.RESOURCE_TRIGGER
    method_permission_name = {
        "list": "read",
    }
    base_permissions = [
        permissions.ACTION_CAN_READ,
        permissions.ACTION_CAN_ACCESS_MENU,
    ]
    list_columns = [
        "id",
        "classpath",
        "created_date",
        "triggerer_id",
    ]
    search_columns = [
        "id",
        "classpath",
        "created_date",
        "triggerer_id",
    ]