安装简述：http://www.360doc.com/content/13/0711/13/11029609_299161821.shtml
其他：
1 linux中将composer.phar 放入全局变量 cp composer.phar /usr/local/bin/composer
2 中国镜像命令：composer config -g repositories.packagist composer http://packagist.phpcomposer.com
3 删除依赖 composer remove monolog/monolog
