我尝试按照本指南安装 Ruby on Rails：http: //elinux.org/RPi_Ruby_on_Rails
当达到指挥
curl -L get.rvm.io | bash -s stable --rails
我收到消息
RROR: Could not find a valid gem 'rails' (>= 0), here is why:
Unable to download data from http://rubygems.org/ - no such name (http://rubygems.org/latest_specs.4.8.gz)
我怎么解决这个问题？