Convert models to use new search includes mechanism

app/models/post_flag.rb

@@ -56,7 +56,7 @@ class PostFlag < ApplicationRecord
     def search(params)
       q = super
 
-      q = q.search_attributes(params, :post, :is_resolved, :reason)
+      q = q.search_attributes(params, :is_resolved, :reason)
       q = q.text_attribute_matches(:reason, params[:reason_matches])
 
       if params[:creator_id].present?
@@ -129,6 +129,10 @@ class PostFlag < ApplicationRecord
     post.uploader_id
   end
 
+  def self.searchable_includes
+    [:post]
+  end
+
   def self.available_includes
     [:post]
   end