CDB-2751 found the problem, missing gem

Gemfile

@@ -28,6 +28,7 @@ gem 'aws-sdk',                 '1.8.5'
 gem 'addressable',             '2.3.2', require: 'addressable/uri'
 
 gem 'ejs',                     '~> 1.1.1'
+gem 'execjs',                  '~> 0.4' # Required by ejs
 
 group :production, :staging do
   gem 'unicorn',               '4.8.2'

Gemfile.lock

@@ -97,6 +97,8 @@ GEM
       ffi (>= 1.3.0)
       mime-types (~> 1.18)
     eventmachine (1.0.3)
+    execjs (0.4.0)
+      multi_json (~> 1.0)
     extlib (0.9.16)
     factory_girl (4.0.0)
       activesupport (>= 3.0.0)
@@ -343,6 +345,7 @@ DEPENDENCIES
   ejs (~> 1.1.1)
   em-pg-client (= 0.2.1)
   eventmachine (= 1.0.3)
+  execjs (~> 0.4)
   factory_girl_rails (~> 4.0.0)
   faraday (= 0.9.0)
   foreman (= 0.46.0)