Postgres HStore

pg_hstore.rb

# /db/migrate/20140119134739_add_hstore.rb
class AddHstore < ActiveRecord::Migration
  def up
    enable_extension 'hstore'
  end
  
  def down
    disable_extension 'hstore'
  end
end

# /db/migrate/2014119134740_add_attr_to_image.rb

class AddAttrToImage < ActiveRecord::Migration
  def change
    add_column :images, :attr, :hstore
  end
end