requiring is mega expensive, lets not do it every request.

app/models/topic.rb

@@ -123,7 +123,7 @@ class Topic < ActiveRecord::Base
     return title unless SiteSetting.title_fancy_entities?
 
     # We don't always have to require this, if fancy is disabled
-    require 'redcarpet'
+    require 'redcarpet' unless defined? Redcarpet
 
     Redcarpet::Render::SmartyPants.render(title)
   end