prepare js polyfills

#238 (comment)

Author: fiedl

app/javascript/packs/matestack-ui-core.js

@@ -1,2 +1,8 @@
-require('../matestack-ui-core/index')
-module.exports = MatestackUiCore
+// // Add polyfills for the asset pipeline
+// // https://github.com/matestack/matestack-ui-core/issues/238#issuecomment-583905838
+//
+// import 'core-js/stable'
+// import 'regenerator-runtime/runtime'
+
+import '../matestack-ui-core/index'
+export default MatestackUiCore

builder/config/webpacker.yml

@@ -11,7 +11,7 @@ default: &default
 
   # Additional paths webpack should lookup modules
   # ['app/assets', 'engine/foo/app/assets']
-  resolved_paths: []
+  resolved_paths: ['./node_modules']
 
   # Reload manifest.json on all requests so we reload latest compiled packs
   cache_manifest: false