*hides behind sofa*

Actually, if the controller only receives a chapter id parameter, and if the chapter was deleted in the meantime, ```Chapter.find_by_id``` will return nil, and then nil.work will also cause an error. Suggest to use ```.try(:work)```. I'm not sure how likely it is to have a link with chapter id only, but if we allow for the possibility in the controller, it means it might, and then it shouldn't error.