Adding RefinaryCMS to existing site (devise/cancancan)

Hi, think the subject kind of says it all. I have an existing site (https://eventpuddle.com/) and want to use RefinaryCMS to manage pages. The app uses devise/cancancan for user managment. Be good to get some pointers as to how to do this. I have looked at https://www.refinerycms.com/guides/with-an-existing-rails-app and it seems relativly stright forward to add RefinaryCMS to the app but what I am not sure about is how I get it to use devise/cancancan (or if this is a bad idea should I use the RefinaryCMS user managment/access. Some pointers woruld be great.