class AddCounterCacheToTags < ActiveRecord::Migration
  def self.up
    add_column :tags, :taggings_count, :integer, :default=>0
    Tag.reset_column_information
    Tag.find(:all).each do |tag|
      tag.update_attribute :taggings_count, tag.taggings.length
    end
  end

  def self.down
    remove_column :tags, :taggings_count
  end
end