FIX: RSS feeds should use `created_at` not `bumped_at`

app/controllers/list_controller.rb

@@ -92,7 +92,7 @@ class ListController < ApplicationController
       @link = "#{Discourse.base_url}/#{filter}"
       @description = I18n.t("rss_description.#{filter}")
       @atom_link = "#{Discourse.base_url}/#{filter}.rss"
-      @topic_list = TopicQuery.new(nil, order: 'activity').public_send("list_#{filter}")
+      @topic_list = TopicQuery.new(nil, order: 'created').public_send("list_#{filter}")
 
       render 'list', formats: [:rss]
     end

lib/topic_query.rb

@@ -34,7 +34,8 @@ class TopicQuery
     'posts' => 'posts_count',
     'activity' => 'bumped_at',
     'posters' => 'participant_count',
-    'category' => 'category_id'
+    'category' => 'category_id',
+    'created' => 'created_at'
   }
 
   def initialize(user=nil, options={})