experiment with factoring comment scores into story hotness

might keep an active story alive on the front page and bury a story
with a "comment graveyard"

app/models/comment.rb

@@ -250,6 +250,8 @@ class Comment < ActiveRecord::Base
       "downvotes = COALESCE(downvotes, 0) + #{downvote.to_i}, " <<
       "confidence = '#{self.calculated_confidence}' WHERE id = " <<
       "#{self.id.to_i}")
+
+    self.story.recalculate_hotness!
   end
 
   def gone_text

app/models/story.rb

@@ -138,10 +138,12 @@ class Story < ActiveRecord::Base
     end
 
     # prevent the submitter's own comments from affecting the score
-    ccount = self.comments.where("user_id != ?", self.user_id).count
+    cpoints = self.comments.where("user_id <> ?",
+      self.user_id).select(:upvotes, :downvotes).map{|c|
+      c.upvotes - c.downvotes }.inject(&:+).to_i
 
     # don't immediately kill stories at 0 by bumping up score by one
-    order = Math.log([ (score + 1).abs + ccount, 1 ].max, base)
+    order = Math.log([ (score + 1).abs + cpoints, 1 ].max, base)
     if score > 0
       sign = 1
     elsif score < 0