The following code (to be run within rails console) may solve your problem, make it worse, or set your hair on fire
. Use at your own risk (and with a backup).
Category.all.each { |c|
c.topic_count = c.topics.length - 1 # -1 for about post
c.save!
}
Alternatively, rake import:ensure_consistency from here might help, but it seems to have destructive side effects.