File es6.patch of Package discourse

Index: discourse/lib/tasks/assets.rake
===================================================================
--- discourse.orig/lib/tasks/assets.rake
+++ discourse/lib/tasks/assets.rake
@@ -180,6 +180,9 @@ def compress_ruby(from, to)
 
   uglified, map =
     Uglifier.new(
+      harmony: true,
+      mangle: false,
+      compress: false,
       comments: :none,
       source_map: {
         filename: File.basename(from),