Add a user index to diary comments

db/migrate/050_add_user_index_to_diary_comments.rb

@@ -0,0 +1,9 @@
+class AddUserIndexToDiaryComments < ActiveRecord::Migration
+  def self.up
+    add_index :diary_comments, [:user_id, :created_at], :name => "diary_comment_user_id_created_at_index"
+  end
+
+  def self.down
+    remove_index :diary_comments, :name => "diary_comment_user_id_created_at_index"
+  end
+end