gistfile1.txt

public function change()
{         
    $table = $this->table('continents', array('id' => false, 'primary_key' => array('name', 'country_id')));
    $table->addColumn('name', 'string')
          ->addColumn('country_id', 'integer')
          ->addForeignKey('country_id', 'country', 'country_id', $options = array())
          ->save();
}