Ruby on Rails

Hello,

I'm currently try to develop my first web application in Ruby on Rails for
myself.

I made a user model with a "role" integer in the database to determine if a user
is:

- Guest
- Editor
- Administrator

I'm using an enum in the model to manage roles availables.

I don't know if it is a good choise ?

Like a CMS, my application manage articles.

- A Guest user can see some private articles and
  post comments like in a blog.
- An editor is like a  guest user but can write articles.
- Administrator can write article and can manage users, attribute roles...

I would like an admin panel only for admin users.
I thought to implement that with an admin namespace and specifics controllers for
admin actions, in this namespace.

About Editor and Guest, I don't know it I should also create differents namespaces ?

Is this practise is a good choise to be conform with Rails principles (DRY, REST full) ?

I would like to know what would be the bests practise in Rails way to implement that.
Your tips or recommendations are welcome ;) !  I would like to learn the best pratices in
Ruby on Rails !