CRUD or not CRUD, I am so lost !

It seems you misunderstand what CRUD is. CRUD isn’t a design concept, it’s just a term used to indicate something provides the basic operations to perform Create, Retrieve, Update and Delete for you. A CRUD-only application can’t have authentication, or anything other than create, retrieve, update or delete for that matter.

Go ahead and implement the features you want, CRUD are just convenience functions.

It seems you misunderstand what CRUD is. CRUD isn't a design concept, it's
just a term used to indicate something provides the basic operations to
perform Create, Retrieve, Update and Delete for you. A CRUD-only application
can't have authentication,

In the Rails core Q&A video from the conference DHH said Jamis Buck
argued persuasively against this. I think it goes

login
  POST /session/create

logout
  DELETE /session/destroy

People have also argued that search can be CRUD.

http://blog.hasmanythrough.com/articles/2006/06/30/cruddy-searches

It doesn't mean these are the best way to do things but people are
thinking about CRUD creatively.

Peter