Add therubyracer gem as javascript library (because passenger doesn't find node...).

Gemfile

@@ -17,7 +17,7 @@ gem 'uglifier', '>= 1.3.0'
 gem 'coffee-rails', '~> 4.0.0'
 
 # See https://github.com/sstephenson/execjs#readme for more supported runtimes
-# gem 'therubyracer', platforms: :ruby
+gem 'therubyracer', platforms: :ruby
 
 # Use jquery as the JavaScript library
 gem 'jquery-rails'

Gemfile.lock

@@ -46,6 +46,7 @@ GEM
       railties (>= 3.0, < 5.0)
       thor (>= 0.14, < 2.0)
     json (1.8.1)
+    libv8 (3.16.14.3)
     mail (2.5.4)
       mime-types (~> 1.16)
       treetop (~> 1.4.8)
@@ -73,6 +74,7 @@ GEM
     rake (10.1.0)
     rdoc (3.12.2)
       json (~> 1.4)
+    ref (1.0.5)
     sass (3.2.12)
     sass-rails (4.0.1)
       railties (>= 4.0.0, < 5.0)
@@ -90,6 +92,9 @@ GEM
       actionpack (>= 3.0)
       activesupport (>= 3.0)
       sprockets (~> 2.8)
+    therubyracer (0.12.0)
+      libv8 (~> 3.16.14.0)
+      ref
     thor (0.18.1)
     thread_safe (0.1.3)
       atomic
@@ -115,5 +120,6 @@ DEPENDENCIES
   rails (= 4.0.2)
   sass-rails (~> 4.0.0)
   sdoc
+  therubyracer
   turbolinks
   uglifier (>= 1.3.0)