Fix rubocop issues, introduce usage of frozen literal to improve performance

app/controllers/auth/confirmations_controller.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Auth::ConfirmationsController < Devise::ConfirmationsController
   layout 'auth'
 end

app/controllers/auth/passwords_controller.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Auth::PasswordsController < Devise::PasswordsController
   layout 'auth'
 end

app/controllers/auth/registrations_controller.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Auth::RegistrationsController < Devise::RegistrationsController
   layout 'auth'
 

app/controllers/auth/sessions_controller.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Auth::SessionsController < Devise::SessionsController
   include Devise::Controllers::Rememberable