discourse/discourse — pull request #600 by kubabrecka (2013-03-31 11:23:27+00:00)
Title: make sure Category.topic_count is consistent with week/year stats

Trying to fix the issue described here: http://meta.discourse.org/t/topic-counts-in-categories/4838

Basically, this patch simply updates `topic_count` the same way that `topics_year`, `topics_week` get calculated.