Merge pull request #29152 from djforth/master

Update to Rails ujs readme

actionview/app/assets/javascripts/README.md

@@ -36,6 +36,16 @@ Require `rails-ujs` into your application.js manifest.
 //= require rails-ujs
 ```
 
+Usage with yarn
+------------
+
+When using with Webpacker gem or your preferred JavaScript bundler. Just add the following to your main JS file and compile.
+
+```javascript
+import Rails from 'rails-ujs';
+Rails.start()
+```
+
 How to run tests
 ------------