rewrite acts_as_taggable_on migration for apps previously using acts_as_taggable_on_steriods

class ActsAsTaggableOnMigration < ActiveRecord::Migration
  def self.up
    change_table :taggings do |t|
      t.column :tagger_id, :integer
      t.column :tagger_type, :string
      t.column :context, :string
    end
    
    add_index :taggings, :context
  end
  
  def self.down
    remove_column :taggings, :context
    remove_column :taggings, :tagger_id
    remove_column :taggings, :tagger_type
    remove_index :taggings, :context
  end
end