Superclass mismatch for class RegistrationController - Overriding Devise Controller - ruby-on-rails

Question

I am trying to override my devise registration controller, with no luck.
I finally got the routes working, but now I'm getting an superclass mismatch for class error.
Heres my setup:
Registration Controller (app/controllers/users/registrations_controller.rb)
class RegistrationsController < Devise::RegistrationsController
def sign_up_params
devise_parameter_sanitizer.sanitize(:sign_up)
params.require(:user).permit(:email, :password, profile_attributes: [:username])
end
def new
super
end
def create
end
def update
super
end
end
Routes
root 'welcome#index'
devise_for :users, :controllers => {:registrations => "users/registrations"}
Views
--edit.html.erb && new.html.erb exist in the folder (app/views/users/registrations)
User Model (just in case)
class User < ActiveRecord::Base
# Include default devise modules. Others available are:
# :confirmable, :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
has_one :profile
accepts_nested_attributes_for :profile
def profile
super || build_profile
end
end
Any idea why this error is appearing?
Thanks!

Answer 1

Your controller is underneath the users directory but does not have a Users module (it is not in the Users namespace, you might say). Either change the controller to this:
module Users
class RegistrationsController < Devise::RegistrationsController
...
end
end
Or move your controller up a directory
app/controllers/registrations_controller.rb

Answer 2

Define your RegistrationsController as below
class Users::RegistrationsController < Devise::RegistrationsController
...
end
By defining the controller as suggested above, you don't need to define the module explicitly.
You get the error because you have placed the RegistrationsController inside users folder.
So, rails expects that RegistrationsController is a class belonging to Users module.