安装 mime-types gem 的时候报错，提示是阿里云的服务器连接错误

Fetching source index from https://ruby.taobao.org/
Resolving dependencies...
Network error while fetching https://rubygems-china.oss.aliyuncs.com/quick/Marshal.4.8/sprockets-2.8.1.gemspec.rz

@huacnlee 可否帮忙看看？