使用 composer create-project yiisoft/yii2-app-basic yii2
报下面错误，
Running composer as root/super user is highly discouraged as packages, plugins and scripts cannot always be trusted
Installing yiisoft/yii2-app-basic (2.0.8)
Installing yiisoft/yii2-app-basic (2.0.8)
Loading from cache
Created project in yii2
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
yiisoft/yii2 2.0.8 requires bower-asset/jquery 2.2.@stable | 2.1.@stable | 1.11.*@stable -> no matching package found.
yiisoft/yii2 2.0.7 requires bower-asset/jquery 2.2.@stable | 2.1.@stable | 1.11.*@stable -> no matching package found.
yiisoft/yii2 2.0.6 requires bower-asset/jquery 2.1.@stable | 1.11.@stable -> no matching package found.
yiisoft/yii2 2.0.5 requires bower-asset/jquery 2.1.@stable | 1.11.@stable -> no matching package found.
Installation request for yiisoft/yii2 >=2.0.5 -> satisfiable by yiisoft/yii2[2.0.5, 2.0.6, 2.0.7, 2.0.8].
Potential causes:
A typo in the package name
The package is not available in a stable-enough version according to your minimum-stability setting
see https://getcomposer.org/doc/04-schema.md#minimum-stability for more details.
Read https://getcomposer.org/doc/articles/troubleshooting.md for further common problems.
登陆的是root权限；
是什么原因，怎么解决；
yii2使用了composer asset plugin来管理需要的bower和npm模块，在安装之前需要先使用下面命令安装composer asset plugin：
composer global require "fxp/composer-asset-plugin:~1.1.1"然后再
composer create-project yiisoft/yii2-app-basic yii2即可安装。