Fix order:comm and comment deletion for unbumped comments

fixes #1351, fixes #1352

db/migrate/20131225002748_add_last_comment_bumped_at_to_posts.rb

@@ -0,0 +1,27 @@
+class AddLastCommentBumpedAtToPosts < ActiveRecord::Migration
+  def self.up
+    execute "SET statement_timeout = 0"
+
+    rename_column :posts, :last_commented_at, :last_comment_bumped_at
+    rename_index :posts, "index_posts_on_last_commented_at", "index_posts_on_last_comment_bumped_at"
+
+    add_column :posts, :last_commented_at, :datetime
+
+    Post.joins(:comments).uniq.find_each do |post|
+      post.update_column(:last_commented_at, post.comments.last.created_at)
+    end
+
+    add_column :comments, :do_not_bump_post, :boolean, :null => false, :default => false
+  end
+
+  def self.down
+    execute "SET statement_timeout = 0"
+
+    remove_column :posts, :last_commented_at
+
+    rename_column :posts, :last_comment_bumped_at, :last_commented_at
+    rename_index :posts, "index_posts_on_last_comment_bumped_at", "index_posts_on_last_commented_at"
+
+    remove_column :comments, :do_not_bump_posts
+  end
+end