出现问题：
C:\Users\len>gem install rails
ERROR: While executing gem ... (Gem::RemoteFetcher::FetchError)
Errno::ETIMEDOUT: A connection attempt failed because the connected party di
d not properly respond after a period of time, or established connection failed
because connected host has failed to respond. - connect(2) for "rubygems.global.
ssl.fastly.net" port 443 (https://api.rubygems.org/quick/Marshal.4.8/sass-3.4.13
.gemspec.rz)
原因是ruby 的gem被和谐了，现在淘宝的ruby工程师架设了rubygems的国内镜像。使用方法如下：
$ gem sources --remove https://rubygems.org/
$ gem sources -a https://ruby.taobao.org/
$ gem sources -l
*** CURRENT SOURCES ***
https://ruby.taobao.org
然后再输入gem install rails，即可安装
