#1 楼@Rei 已经换成了淘宝镜像
最后得出了这些错误
An error occurred while installing mysql2 (0.3.18), and
Bundler cannot continue.
Make sure that gem install mysql2 -v '0.3.18' succeeds
before bundling.
run bundle exec spring binstub --all
bundler: command not found: spring
Install missing gem executables with bundle install