Add option to be notified when a followed user posts (#13546)

* Add bell button

Fix #4890

* Remove duplicate type from post-deployment migration

* Fix legacy class type mappings

* Improve query performance with better index

* Fix validation

* Remove redundant index from notifications

app/workers/refollow_worker.rb

@@ -11,6 +11,7 @@ class RefollowWorker
 
     target_account.passive_relationships.where(account: Account.where(domain: nil)).includes(:account).reorder(nil).find_each do |follow|
       reblogs = follow.show_reblogs?
+      notify  = follow.notify?
 
       # Locally unfollow remote account
       follower = follow.account
@@ -18,7 +19,7 @@ class RefollowWorker
 
       # Schedule re-follow
       begin
-        FollowService.new.call(follower, target_account, reblogs: reblogs)
+        FollowService.new.call(follower, target_account, reblogs: reblogs, notify: notify)
       rescue Mastodon::NotPermittedError, ActiveRecord::RecordNotFound, Mastodon::UnexpectedResponseError, HTTP::Error, OpenSSL::SSL::SSLError
         next
       end