public function add($gitUrl, $path = null)
    {
        $this->clearAll();
        $this->addCommandName(sprintf('%s %s', self::SUBMODULE_COMMAND, self::SUBMODULE_ADD_COMMAND));
        $this->addCommandArgument($gitUrl);
        if (null !== $path) {
            $this->addCommandSubject($path);
        }

        return $this->getCommand();
    }