Do I need a “Users” controller when using Devise i

I am a Rails newbie. I am working on a small Rails4 project trying to improve my skills. I am loosely following M.Hartl's tutorial.

As per the tutorial a custom user authentication is built. However I would like to use Devise for User authentication. Do I still need to have a Users controller as in the tutorial? In which cases should I use/not use a Users controller when already using Devise?

Concerning the tutorial, do I just skip the controller generating part or do I have to map the actions to Devise?

You only need a users controller if you want to manage users separately from the normal signup/update process. I have a users controller so that admins can manage (create, edit, update, delete) users independently of the normal devise signup/update process.

The conflict with devise is probably because you have devise_for :users … in your routes file to set up devise and also have resources :users for your UsersController. This means that devise and your UsersController will be trying to share some of the same /users routes. You need to separate them out by changing the path that one of them is mapped to. You could either add, for example, :path => 'u' to your devise_for statement so that devise routes are mapped to /u and won't conflict with your UsersController on /users. Alternatively you could leave the devise_for alone (therefore still using /users) and instead change your UsersController routing to, for example, resources :users_admin, :controller => 'users' which would move your UsersControllers routes to be mapped to /users_admin. Note that this would change the path helpers from, for example, users_path to users_admin_path.

UPDATE

Following your comment/edit, I've had a quick look at the tutorial and I think that devise basically gives you the equivalent functionality of the user-related functionality which is developed from section 5.4 to about sections 9.1 or 9.2. (plus some extra stuff, for example, email confirmation, password reset, account lockout etc.). However, that doesn't mean that it's a drop-in replacement for that functionality, if you want to try and merge Devise with that tutorial. There are some things that look like they would work (e.g. Devise also defines a current_user method), but the routes etc. would be different, and devise splits things up into more controllers (separate controllers for registration, sign in/out, password reset…). The admin-type functionality (like in sections 2.2, 9.3, 9.4 - create/edit/delete/list other users) is what I've added a separate UsersController for in my app. Devise doesn't define a UsersController, but does use the users routes if you do devise_for :users without a path as I mentioned above.

So, more specifically:

You would only need a UsersController if you want to enable admin-type functionality allowing viewing/editing/deleting all users.
If you wanted to use devise in the tutorial, it would probably need some work to massage things to fit, changing helper links on pages etc. Sorry I'm not more specific; I haven't done that tutorial.

You would be missing out on the extra understanding that comes from doing it all manually yourself, but devise is a popular engine, so it's good to know as well. If you have the time, you could do the tutorial entirely, and then again with devise! It would help you understand some of the kind of stuff devise is doing behind the scenes. P.S: It can be instructive to look at the devise source code, even if you don't understand it all immediately.