Cant add users

I found that hydra-roles-management is not working with the latest hydra gems used in our administrative hydra-head MIRA.  I've updated the code such that adding roles, and adding users to roles will now work.  Problems seemed to stem from changes in rails bootstrap forms.
How about just making "Cancel" a link with `class: 'btn btn-default'`? Then there's no need to handle it in the controllers.