chore: Delete related notifications if a conversation is deleted (#2592)

db/migrate/20210708140842_remove_notifications_without_primary_actor.rb

@@ -0,0 +1,9 @@
+class RemoveNotificationsWithoutPrimaryActor < ActiveRecord::Migration[6.0]
+  def change
+    deleted_ids = []
+    Notification.where(primary_actor_type: 'Conversation').pluck(:primary_actor_id).uniq.each_slice(1000) do |id_list|
+      deleted_ids << id_list - Conversation.where(id: id_list).pluck(:id)
+    end
+    Notification.where(primary_actor_type: 'Conversation', primary_actor_id: deleted_ids).destroy_all
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2021_06_23_155413) do
+ActiveRecord::Schema.define(version: 2021_07_08_140842) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_stat_statements"