FIX: deprecate TopicAssigner (#221)

Delegate to assigner and add deprecation note

lib/topic_assigner.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+class ::TopicAssigner
+  def self.backfill_auto_assign
+    deprecation_note
+    Assigner.backfill_auto_assign
+  end
+
+  def self.assigned_self?(text)
+    deprecation_note
+    Assigner.assigned_self?(text)
+  end
+
+  def self.auto_assign(post, force: false)
+    deprecation_note
+    Assigner.auto_assign(post, force)
+  end
+
+  def self.is_last_staff_post?(post)
+    deprecation_note
+    Assigner.is_last_staff_post?(post)
+  end
+
+  def self.mentioned_staff(post)
+    deprecation_note
+    Assigner.mentioned_staff(post)
+  end
+
+  def self.publish_topic_tracking_state(topic, user_id)
+    deprecation_note
+    Assigner.publish_topic_tracking_state(topic, user_id)
+  end
+
+  def initialize(target, user)
+    self.class.deprecation_note
+    Assigner.new(target, user)
+  end
+
+  def self.deprecation_note
+    Discourse.deprecate("TopicAssigner class is deprecated, use Assigner", since: "2.8", drop_from: "2.9")
+  end
+end

plugin.rb

@@ -33,6 +33,7 @@ after_initialize do
   require File.expand_path('../jobs/regular/remind_user.rb', __FILE__)
   require File.expand_path('../jobs/regular/assign_notification.rb', __FILE__)
   require File.expand_path('../jobs/regular/unassign_notification.rb', __FILE__)
+  require 'topic_assigner'
   require 'assigner'
   require 'pending_assigns_reminder'