I think friendly_id actually modifies model `.find` methods.

i.e.
`Discussion.find_by_key(   )` should be just `Discussion.find(   )`
and this would mean could still use: 
`load_and_authorize_resource`

in the case of the group model I think we should leave it as is because there is a fancy `group` method which looks up based on `id` or `group_id`