ruby - 为什么我会收到“没有要加载的文件”？

Question

我正在安装 Open Project 并运行bundle exec rails server并得到：

root@bistro2:/home/openproject/openproject# bundle exec
/usr/lib/ruby/vendor_ruby/bundler/rubygems_ext.rb:8:in `require': no such file to load -- rubygems (LoadError)
        from /usr/lib/ruby/vendor_ruby/bundler/rubygems_ext.rb:8
        from /usr/lib/ruby/vendor_ruby/bundler.rb:11:in `require'
        from /usr/lib/ruby/vendor_ruby/bundler.rb:11
        from /usr/bin/bundle:4:in `require'
        from /usr/bin/bundle:4
root@bistro2:/home/openproject/openproject#