改变宝石来源
# list gem sources:
gem sources -l
# remove default gem source:
gem sources -r https://rubygems.org/
# add other gem sources:
gem sources -a https://ruby.taobao.org/
# list gem sources:
gem sources -l
# remove default gem source:
gem sources -r https://rubygems.org/
# add other gem sources:
gem sources -a https://ruby.taobao.org/