1，安装依赖包
★问题：Unable to download data from https://rubygems.org/ - SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed (https://api.rubygems.org/specs.4.8.gz)
解决办法：
▶执行命令：
gem sources -r https://rubygems.org
gem sources -a http://rubygems.org
安装完后，改回来：
gem sources -r http://rubygems.org
gem sources -a https://rubygems.org
使用国内提供的RubyGems镜像源，提速：
gem sources -r https://rubygems.org/
gem sources -a http://ruby.taobao.org/