¿El servidor Rails no se inicia?

Question

cuando doy el comando "rieles s" siguiente error viene por favor ayúdenme! Todavía estoy en el proyecto de carriles y luego, mando

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

añadir

gem 'therubyracer' 

a su Gemfile y ejecutar

bundle 

comando

Answer 2

Es necesario instalar un tiempo de ejecución de Javascript tales como:

gem install therubyracer

o

http://nodejs.org/

Este es utilizado por la tubería de activos en rieles 3 para compilar el coffeescript.