title: ExecJS::RuntimeUnavailable in Rails 4.1.4
body: <p><strong>UPDATE</strong> : Things are now working !</p>
  
  <p>Thanks to <a href="https://stackoverflow.com/users/2300000/deep">deep</a>, I installed node.js then got a TZInfo::DataSourceNotFound error wich got resolved by adding <code>gem 'tzinfo-data', platforms: [:mingw, :mswin]</code> and <code>bundle update</code>.</p>
  
  <p>Thank you sir !</p>
  
  <hr>
  
  <p>First of all, I am a complete beginner on rails (just so that you get how beginner I am : I feel as being an expert for just posting here) and this is my first question here so please excuse me if I'm not very clear.</p>
  
  <p>So, I am a windows 7 user, learning rails with the One Month course and I encounter an error while trying to :</p>
  
  <pre><code>$ rake routes
  rake aborted!
  ExecJS::RuntimeUnavailable: Could not find a JavaScript runtime. See https://git
  hub.com/sstephenson/execjs for a list of available runtimes.
  c:/Users/Marc Montagne/Desktop/pinteresting/config/application.rb:7:in `&lt;top (re
  quired)&gt;'
  c:/Users/Marc Montagne/Desktop/pinteresting/Rakefile:4:in `&lt;top (required)&gt;'
  (See full trace by running task with --trace)
  </code></pre>
  
  <p>or </p>
  
  <pre><code>$ rails server
  c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/execjs-2.0.2/lib/execjs/run
  times.rb:51:in `autodetect': Could not find a JavaScript runtime. See https://gi
  thub.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUn
  available)
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/execjs-2.0.2/l
  ib/execjs.rb:5:in `&lt;module:ExecJS&gt;'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/execjs-2.0.2/l
  ib/execjs.rb:4:in `&lt;top (required)&gt;'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/uglifier-2.4.0
  /lib/uglifier.rb:3:in `require'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/uglifier-2.4.0
  /lib/uglifier.rb:3:in `&lt;top (required)&gt;'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/
  lib/bundler/runtime.rb:72:in `require'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/
  lib/bundler/runtime.rb:72:in `block (2 levels) in require'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/
  lib/bundler/runtime.rb:70:in `each'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/
  lib/bundler/runtime.rb:70:in `block in require'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/
  lib/bundler/runtime.rb:59:in `each'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/
  lib/bundler/runtime.rb:59:in `require'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/
  lib/bundler.rb:132:in `require'
          from c:/Users/Marc Montagne/Desktop/pinteresting/config/application.rb:7
  :in `&lt;top (required)&gt;'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.1.4
  /lib/rails/commands/commands_tasks.rb:79:in `require'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.1.4
  /lib/rails/commands/commands_tasks.rb:79:in `block in server'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.1.4
  /lib/rails/commands/commands_tasks.rb:76:in `tap'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.1.4
  /lib/rails/commands/commands_tasks.rb:76:in `server'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.1.4
  /lib/rails/commands/commands_tasks.rb:40:in `run_command!'
          from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.1.4
  /lib/rails/commands.rb:17:in `&lt;top (required)&gt;'
          from bin/rails:4:in `require'
          from bin/rails:4:in `&lt;main&gt;'
  </code></pre>
  
  <p>All that I understand is that I have a problem with ExecJS. As a total beginner I don't even know what ExecJS is.</p>
  
  <p>I read the great thread <a href="https://stackoverflow.com/questions/12520456/execjsruntimeerror-on-windows-trying-to-follow-rubytutorial/14118913#14118913">#12520456</a> and while editing runtimes.rb didn't fix my problem, it still gave me a better understanding of the situation and the willingness to solve my problem by fixing it and not "ignoring it" by adding node.js especially given the fact that I could run my server before and that I want to fix what I basically broke.</p>
  
  <p>What I mean by that is that I think I did something wrong when editing the PATH (I don't even know what this is) of my Windows environment for fixing an issue I had with installing Heroku. I remember editing that part as I read it somewhere and while it seemed to have fixed my Heroku issue I think it messed up the rest.</p>
  
  <p>Thank you in advance for your help and understanding.</p>