devise + strong_parameters

_routes.rb

# config/routes.rb

MyApp::Application.routes.draw do
  devise_for :users, controllers: {
    registrations: "users/registrations"
  }
end

registrations_controller.rb

# app/controllers/users/registrations_controller.rb

class Users::RegistrationsController < Devise::RegistrationsController
  protected

  def resource_params
    params.require(resource_name).permit(:email, :password, :password_confirmation)
  end
end