初始化报错 [ 未指定版本 ]

今天刚把这个问题解决，我是按照新的官方guide重装了个项目，然后拷贝了composer.json的内容，如下

{
    "name": "yiisoft/yii2-app-basic",
    "description": "Yii 2 Basic Application Template",
    "keywords": ["yii2", "framework", "basic", "application template"],
    "homepage": "http://www.yiiframework.com/",
    "type": "project",
    "license": "BSD-3-Clause",
    "support": {
        "issues": "https://github.com/yiisoft/yii2/issues?state=open",
        "forum": "http://www.yiiframework.com/forum/",
        "wiki": "http://www.yiiframework.com/wiki/",
        "irc": "irc://irc.freenode.net/yii",
        "source": "https://github.com/yiisoft/yii2"
    },
    "minimum-stability": "dev",
    "require": {
        "php": ">=5.4.0",
        "yiisoft/yii2": "*",
        "yiisoft/yii2-bootstrap": "*",
        "yiisoft/yii2-swiftmailer": "*"
    },
    "require-dev": {
        "yiisoft/yii2-codeception": "*",
        "yiisoft/yii2-debug": "*",
        "yiisoft/yii2-gii": "*",
        "yiisoft/yii2-faker": "*"
    },
    "config": {
        "process-timeout": 1800
    },
    "scripts": {
        "post-create-project-cmd": [
            "yii\\composer\\Installer::postCreateProject"
        ]
    },
    "extra": {
        "yii\\composer\\Installer::postCreateProject": {
            "setPermission": [
                {
                    "runtime": "0777",
                    "web/assets": "0777",
                    "yii": "0755"
                }
            ],
            "generateCookieValidationKey": [
                "config/web.php"
            ]
        },
        "asset-installer-paths": {
            "npm-asset-library": "vendor/npm",
            "bower-asset-library": "vendor/bower"
        }
    }
}

1.在项目外部执行：composer global require "fxp/composer-asset-plugin:1.0.0-beta2"
2.进入项目根目录，把刚拷贝的内容替换composer.json的内容，然后执行：composer update --prefer-dist，此处应该会让你填写Git账号，之前没有的，要到Git官网注册一个账号，按提示输入用户名密码就ok了

没有解决我遇到的问题。。。