Redmine

class CreateTaggings < ActiveRecord::Migration

  def self.up

    create_table :taggings, :id => false do |t|

      t.column :tag_id, :integer

      t.column :container_id, :integer

      t.column :container_type, :string

    end

    add_index :taggings, [:container_id, :container_type, :container_id], :name => "taggings_ids", :unique => true 

  end

  def self.down

    drop_table :taggings

  end

end