[Solved] Error 500 We're sorry, but something went wrong" in users sign in page

The production log in my gitlab log folder reads like this

Started GET "/users/sign_in" for ***.***.***.*** at 2015-04-07 23:15:55 +0200
Processing by SessionsController#new as HTML
Completed 500 Internal Server Error in 199ms

ActionView::Template::Error (Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes.
  (in /home/git/gitlab/app/assets/javascripts/application.js.coffee)):
     8:   = favicon_link_tag 'favicon.ico'
     9:   = stylesheet_link_tag    "application", :media => "all"
    10:   = stylesheet_link_tag    "print", :media => "print"
    11:   = javascript_include_tag "application"
    12:   = csrf_meta_tags
    13:   = include_gon
    14:   %meta{name: 'viewport', content: 'width=device-width, initial-scale=1, maximum-scale=1'}
  app/views/layouts/_head.html.haml:11:in `_app_views_layouts__head_html_haml___1059026759__543098138'
  app/views/layouts/devise.html.haml:3:in `_app_views_layouts_devise_html_haml__971540335__543693558'
  app/controllers/sessions_controller.rb:25:in `new'

I tried compiling the assets again but didnt solve it. Any idea on how to solve it?

See my reply to my post:
http://forum.gitlab.com/t/upgrade-to-7-9-3-failed-could-not-precompile-assets-with-message-could-not-find-javasscript-runtime/571