Composer下载私有GitHub存储库

我无法下载github私有repos与composer

php composer.phar update 

我得到以下错误

"https://api.github.com/repos/company/private1"文件不能已下载的HTTP/1.1 404 Not Found

，但我可以很容易地下载这些私人回购使用git clone

Composer.json

"repositories": [
    {
        "type": "vcs",
        "url": "git@github.com:company/private1.git",
        "options": {
            "ssh2": {
                "username": "githubusername",
                "pubkey_file": "/home/username/.ssh/id_rsa.pub",
                "privkey_file": "/home/username/.ssh/id_rsa"
            }
        }
    },
    {
        "type": "vcs",
        "url": "git@github.com:company/private2.git",
        "options": {
            "ssh2": {
                "username": "githubusername",
                "pubkey_file": "/home/username/.ssh/id_rsa.pub",
                "privkey_file": "/home/username/.ssh/id_rsa"
            }
        }
    }
],
"require": {
    "php": ">=5.4.3",
    "zendframework/zendframework": ">2.1.3",
    "doctrine/mongodb-odm": "dev-master",
    "doctrine/doctrine-mongo-odm-module": "dev-master",
    "company/private": "dev-master",
    "company/private2": "dev-master"
}

我试过了，但是没有用

SSH2 PECL也被启用。

我还创建了配置文件vim ~/home/.ssh/config

包含以下细节

host www.github.com
User githubusername
HostName github.com
IdentityFile /home/username/.ssh/id_rsa

但是我仍然无法使用composer下载私有repos