Update uglifier config

Author: nygrenh

config/environments/production.rb

@@ -33,7 +33,10 @@
   config.serve_static_files = false
 
   # Compress JavaScripts and CSS.
-  config.assets.js_compressor = Uglifier.new(harmony: true)
+  config.assets.configure do |env|
+    env.js_compressor  = :uglifier # or :closure, :yui
+    env.css_compressor = :sass   # or :yui
+  end
   # config.assets.css_compressor = :sass
 
   # Do not fallback to assets pipeline if a precompiled asset is missed.