Added ability to update a wiki

ok, I get it now, duh. We did this in the other app I just needed to translate it to haml.  - M
This isn't going to work. Remember the 'Collaboration' is a model in and of itself, so you don't want to loop through those models, you want the 'wikis_i_am_collaborating_on'  - that collection is the actual Wiki models that are linked through the Collaboration.