Here we want to render a custom page like the user's profile page after a successful account updation.The solution is fairly simple,however one  prerequisite i am assuming that we have already run rails generate devise:controller user command.

Now consider Users::RegistrationsController and write after_update_path_for (resource) method as depicted below:

class Users::RegistrationsController < Devise::RegistrationsController

   def after_update_path_for(resource)
      profile_path(resource)
    end

end

and config/routes.rb file should look like this :

Rails.application.routes.draw do
   
     devise_for :users, :controllers => {:registrations => "users/registrations"}
     get 'profile' => 'users#profile'

end

So here after the  account updation instead of going to the default page as managed by devise gem we are rendered to the user's profile page as we have overridden the after_update_path_for (resource)  method.

A slight deviation here , the after_sign_in_path method can also be added to the Users::SessionsController instead of the application_controller. Both are the accepted remedies for the usual problem of rendering a custom page after a successful login.

class Users::SessionsController < Devise::SessionsController 

     def after_sign_in_path_for(resource) 
        profile_path
     end

end

So here after a successful login the user's profile page will be rendered and the same routes.rb file will suffice our purpose.

Thank you .