don't send devise notifications to the ghost user

app/models/user.rb

@@ -1069,6 +1069,7 @@ class User < ActiveRecord::Base
 
   # Added according to https://github.com/plataformatec/devise/blob/7df57d5081f9884849ca15e4fde179ef164a575f/README.md#activejob-integration
   def send_devise_notification(notification, *args)
+    return true unless can?(:receive_notifications)
     devise_mailer.send(notification, self, *args).deliver_later
   end