bad response Not Found 404 (http

先查看当前的ruby源

$ gem sources -l 

移除https://rubygems.org/

$ gem source -r https://gems.ruby-china.org/　

添加新的ruby源

$ gem sources -a https://gems.ruby-china.com/

查看当前ruby源确保只有一个确保只有
gems.ruby-china.com/