Merge pull request rails#53978 from GaiheiluKamei/fix-redundant-codes-in-getting-started

Remove redundant codes in section 16.4 of  getting_started.md [ci skip]

Author: fatkodima

guides/source/getting_started.md

@@ -2335,7 +2335,6 @@ Notifications module.
 class Product < ApplicationRecord
   include Notifications
 
-  has_many :subscribers, dependent: :destroy
   has_one_attached :featured_image
   has_rich_text :description