public function connect(array $config)
    {
        $connection = $this->createConnection($config);

        $this->validateCredentials($config);

        // For basic authentication we need an Authorization
        // header to be set. We add it to the request here.
        $this->addHeader(
            'Authorization',
            'Basic ' . base64_encode(
                array_get($config, 'identifier') . ':' . array_get($config, 'secret')
            )
        );

        return $connection;
    }