adding execjs and therubyracer to fix js issue on ubuntu

Gemfile

@@ -63,3 +63,7 @@ gem 'minitest', '~> 4.0', :require=> "minitest/autorun"
 
 # To use debugger
 # gem 'debugger'
+
+gem 'execjs'
+gem 'therubyracer'
+

Gemfile.lock

@@ -115,6 +115,7 @@ GEM
       thor (>= 0.14, < 2.0)
     json (1.7.7)
     kgio (2.8.0)
+    libv8 (3.16.14.3)
     listen (0.7.3)
     lumberjack (1.0.3)
     mail (2.5.3)
@@ -162,6 +163,7 @@ GEM
     rb-fsevent (0.9.3)
     rdoc (3.12.2)
       json (~> 1.4)
+    ref (1.0.5)
     rspec (2.14.1)
       rspec-core (~> 2.14.0)
       rspec-expectations (~> 2.14.0)
@@ -200,6 +202,9 @@ GEM
     sqlite3 (1.3.7)
     temple (0.6.3)
     terminal-table (1.4.5)
+    therubyracer (0.12.0)
+      libv8 (~> 3.16.14.0)
+      ref
     thor (0.18.1)
     tilt (1.3.7)
     treetop (1.4.12)
@@ -224,6 +229,7 @@ DEPENDENCIES
   brakeman
   bundler-audit
   coffee-rails (~> 3.2.1)
+  execjs
   foreman
   gauntlt
   guard-brakeman
@@ -240,5 +246,6 @@ DEPENDENCIES
   rspec-rails
   sass-rails (~> 3.2.3)
   sqlite3
+  therubyracer
   uglifier (>= 1.0.3)
   unicorn