use an async worker to notify users about policy update

app/models/setting.rb

@@ -51,9 +51,7 @@ class Setting < ActiveRecord::Base
   def notify_privacy_policy_changed
     return unless name == 'privacy_body'
 
-    NotificationCenter.call type: :notify_privacy_policy_changed,
-                            receiver: User.all,
-                            attached_object: self
+    NotifyPrivacyUpdateWorker.perform_async(id)
   end
 
   def value

app/workers/notify_privacy_update_worker.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+# Send an email to all users (with role member) in the database to alert them about a privacy policy change
+class NotifyPrivacyUpdateWorker
+  include Sidekiq::Worker
+
+  def perform(setting_id)
+    setting = Setting.find(setting_id)
+
+    # notify all users
+    NotificationCenter.call type: :notify_privacy_policy_changed,
+                            receiver: User.with_role(:member).all,
+                            attached_object: setting
+  end
+
+end