public function addField ( $name, $content, $boost = null )
    {
        if ( !is_array( $content ) )
        {
            $content = array( $content );
        }

        if (array_key_exists($name, $this->Doc))
        {
            $this->Doc[$name]['content'] = array_merge($this->Doc[$name]['content'], $content);
        }
        else
        {
            $this->Doc[$name]['content'] =  $content;
        }
        $this->Doc[$name]['boost'] = $boost;
    }