Pass group ID to path to fix broken link

[nwoodthorpe]

These links were broken in stafftools. They were generating links like: http://0.0.0.0:5000/stafftools/groups/groupslughere using the slug instead of the ID.

We could also change the controller to find the Group by slug instead, but the spec asserts it uses the ID so I'm guessing that's the behaviour we want.

@tarebyte

Error:

ActiveRecord::RecordNotFound (Couldn't find Group):
app/controllers/stafftools/groups_controller.rb:11:in `set_group'

[tarebyte]

👍