<p>When trying to run "rails server", it refuses to start with the error message:</p>

<p>/var/lib/gems/1.9.1/gems/execjs-2.0.2/lib/execjs/runtimes.rb:51:in <code>autodetect': Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)<br>
        from /var/lib/gems/1.9.1/gems/execjs-2.0.2/lib/execjs.rb:5:in</code><a>module:ExecJS</a>'<br>
        from /var/lib/gems/1.9.1/gems/execjs-2.0.2/lib/execjs.rb:4:in <code><top (required)>'<br>
        from /var/lib/gems/1.9.1/gems/uglifier-2.3.1/lib/uglifier.rb:3:in</code>require'<br>
        from /var/lib/gems/1.9.1/gems/uglifier-2.3.1/lib/uglifier.rb:3:in <code><top (required)>'<br>
        from /var/lib/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in</code>require'<br>
        from /var/lib/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in <code>block (2 levels) in require'<br>
        from /var/lib/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in</code>each'<br>
        from /var/lib/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in <code>block in require'<br>
        from /var/lib/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in</code>each'<br>
        from /var/lib/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in <code>require'<br>
        from /var/lib/gems/1.9.1/gems/bundler-1.3.5/lib/bundler.rb:132:in</code>require'<br>
        from /home/roland/osm/openstreetmap-website/config/application.rb:17:in <code><top (required)>'<br>
        from /var/lib/gems/1.9.1/gems/railties-4.0.1/lib/rails/commands.rb:74:in</code>require'<br>
        from /var/lib/gems/1.9.1/gems/railties-4.0.1/lib/rails/commands.rb:74:in <code>block in <top (required)>'<br>
        from /var/lib/gems/1.9.1/gems/railties-4.0.1/lib/rails/commands.rb:71:in</code>tap'<br>
        from /var/lib/gems/1.9.1/gems/railties-4.0.1/lib/rails/commands.rb:71:in <code><top (required)>'<br>
        from script/rails:6:in</code>require'<br>
        from script/rails:6:in `'</p>

<p>Probably a dependency must be adjusted.</p>

<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<br>Reply to this email directly or <a href='https://github.com/openstreetmap/openstreetmap-website/issues/593'>view it on GitHub</a>.<img src='https://github.com/notifications/beacon/uTRSc6ihLa7Shf84BpiOppz8XTQB8rVAjgWAMso5HafzLBLPLWyJfpC10TWCM-26.gif' height='1' width='1'></p>