Add notifications when a reblogged status has been updated

app/models/status.rb

@@ -62,6 +62,7 @@ class Status < ApplicationRecord
   has_many :favourites, inverse_of: :status, dependent: :destroy
   has_many :bookmarks, inverse_of: :status, dependent: :destroy
   has_many :reblogs, foreign_key: 'reblog_of_id', class_name: 'Status', inverse_of: :reblog, dependent: :destroy
+  has_many :reblogged_by_accounts, through: :reblogs, class_name: 'Account', foreign_key: 'account_id'
   has_many :replies, foreign_key: 'in_reply_to_id', class_name: 'Status', inverse_of: :thread
   has_many :mentions, dependent: :destroy, inverse_of: :status
   has_many :active_mentions, -> { active }, class_name: 'Mention', inverse_of: :status

app/services/fan_out_on_write_service.rb

@@ -34,6 +34,7 @@ def check_race_condition!
   def fan_out_to_local_recipients!
     deliver_to_self!
     notify_mentioned_accounts!
+    notify_about_update! if update?
 
     case @status.visibility.to_sym
     when :public, :unlisted, :private
@@ -64,6 +65,14 @@ def notify_mentioned_accounts!
     end
   end
 
+  def notify_about_update!
+    @status.reblogged_by_accounts.merge(Account.local).select(:id).reorder(nil).find_in_batches do |accounts|
+      LocalNotificationWorker.push_bulk(accounts) do |account|
+        [account.id, @status.id, 'Status', 'update']
+      end
+    end
+  end
+
   def deliver_to_all_followers!
     @account.followers_for_local_distribution.select(:id).reorder(nil).find_in_batches do |followers|
       FeedInsertWorker.push_bulk(followers) do |follower|