Rails服务器无法启动？

Question

当我发出命令“rails s”出现以下错误时请帮助我！我依然在轨项目，然后给这个命令

root@ubuntu:~# cd mon 
root@ubuntu:~/mon# rails s 
/usr/lib/ruby/gems/1.8/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 available runtimes. (ExecJS::RuntimeUnavailable) 
    from /usr/lib/ruby/gems/1.8/gems/execjs-1.3.0/lib/execjs.rb:5 
    from /usr/lib/ruby/gems/1.8/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `require' 
    from /usr/lib/ruby/gems/1.8/gems/coffee-script-2.2.0/lib/coffee_script.rb:1 
    from /usr/lib/ruby/gems/1.8/gems/coffee-script-2.2.0/lib/coffee-script.rb:1:in `require' 
    from /usr/lib/ruby/gems/1.8/gems/coffee-script-2.2.0/lib/coffee-script.rb:1 
    from /usr/lib/ruby/gems/1.8/gems/coffee-rails-3.2.2/lib/coffee-rails.rb:1:in `require' 
    from /usr/lib/ruby/gems/1.8/gems/coffee-rails-3.2.2/lib/coffee-rails.rb:1 
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.3/lib/bundler/runtime.rb:68:in `require' 
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.3/lib/bundler/runtime.rb:68:in `require' 
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.3/lib/bundler/runtime.rb:66:in `each' 
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.3/lib/bundler/runtime.rb:66:in `require' 
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.3/lib/bundler/runtime.rb:55:in `each' 
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.3/lib/bundler/runtime.rb:55:in `require' 
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.3/lib/bundler.rb:119:in `require' 
    from /root/mon/config/application.rb:7 
    from /usr/lib/ruby/gems/1.8/gems/railties-3.2.3/lib/rails/commands.rb:53:in `require' 
    from /usr/lib/ruby/gems/1.8/gems/railties-3.2.3/lib/rails/commands.rb:53 
    from /usr/lib/ruby/gems/1.8/gems/railties-3.2.3/lib/rails/commands.rb:50:in `tap' 
    from /usr/lib/ruby/gems/1.8/gems/railties-3.2.3/lib/rails/commands.rb:50 
    from script/rails:6:in `require' 
    from script/rails:6 

Answer 1

添加

gem 'therubyracer' 

您Gemfile和运行

bundle 

命令

Answer 2

你需要安装一个JavaScript运行，如：

gem install therubyracer

或

http://nodejs.org/

这是由rails 3中的资产管道用于编译咖啡脚本。