* Denormalized post versions. Testing has shown it reduces the size

of the table 66%.

app/models/post_version.rb

@@ -1,6 +0,0 @@
-class PostVersion < ActiveRecord::Base
-  class Error < Exception ; end
-  
-  validates_presence_of :updater_id, :updater_ip_addr
-  belongs_to :post
-end