FEATURE: Live updates for user's messages page.

https://meta.discourse.org/t/group-inbox-messages-not-updated-for-new-posts/38189

app/models/user_archived_message.rb

@@ -2,7 +2,9 @@ class UserArchivedMessage < ActiveRecord::Base
   belongs_to :user
   belongs_to :topic
 
-  def self.move_to_inbox!(user_id, topic_id)
+  def self.move_to_inbox!(user_id, topic)
+    topic_id = topic.id
+
     return if (TopicUser.where(
       user_id: user_id,
       topic_id: topic_id,
@@ -12,13 +14,16 @@ class UserArchivedMessage < ActiveRecord::Base
     UserArchivedMessage.where(user_id: user_id, topic_id: topic_id).destroy_all
     trigger(:move_to_inbox, user_id, topic_id)
     MessageBus.publish("/topic/#{topic_id}", { type: "move_to_inbox" }, user_ids: [user_id])
+    publish_topic_tracking_state(topic, false)
   end
 
-  def self.archive!(user_id, topic_id)
+  def self.archive!(user_id, topic)
+    topic_id = topic.id
     UserArchivedMessage.where(user_id: user_id, topic_id: topic_id).destroy_all
     UserArchivedMessage.create!(user_id: user_id, topic_id: topic_id)
     trigger(:archive_message, user_id, topic_id)
     MessageBus.publish("/topic/#{topic_id}", { type: "archived" }, user_ids: [user_id])
+    publish_topic_tracking_state(topic, true)
   end
 
   def self.trigger(event, user_id, topic_id)
@@ -28,6 +33,14 @@ class UserArchivedMessage < ActiveRecord::Base
       DiscourseEvent.trigger(event, user: user, topic: topic)
     end
   end
+
+  private
+
+    def self.publish_topic_tracking_state(topic, archived)
+      TopicTrackingState.publish_private_message(
+        topic, archived: archived
+      )
+    end
 end
 
 # == Schema Information