Flutter配置

　使用镜像

1 export PUB_HOSTED_URL=https://pub.flutter-io.cn
2 export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn
git clone github上的flutter
3 git clone -b alpha https://github.com/flutter/flutter.git
添加flutter相关工具到path中：
4 export PATH="$PWD/flutter/bin:$PATH"
5 cd ./flutter
运行以下命令查看是否需要安装其它依赖项来完成安装：
6 flutter doctor