title: Override ActiveAdmin resource controller for only some resources
body: <p>In my app, some of the resources need to be hippa compliant and we do some things to fit in with that need - using ActiveAdmin::Comments as a sort of git commenting system, and hiding the index collection if there's no filtering applied, etc.</p>
  
  <p>All the hippa resources are written totally generically within the normal ActiveAdmin.register [resource] -- so rather than cutting and pasting the code multiple times to every resource, I was hoping there was a way for me to override the base resource controller elsewhere and then have these specific resources pull from the HippaResource rather than the base?  Or is there a way to extend or include the generic code used?</p>