我在我的机器上安装ruby on rails时遇到了问题。我一直在关注“使用Rails进行敏捷Web开发”这本书,到目前为止,一切都很顺利。rails server/home/myname/.gem/ruby/1.9.1/gems/execjs-1.3.0/lib/execjs/runtimes.rb:50:in `autodetect': Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of availabl