Upgrade to Rails 7, new JS build setup

app/javascript/controllers/index.js

@@ -0,0 +1,11 @@
+// Import and register all your controllers from the importmap under controllers/*
+
+import { application } from "controllers/application"
+
+// Eager load all controllers defined in the import map under controllers/**/*_controller
+import { eagerLoadControllersFrom } from "@hotwired/stimulus-loading"
+eagerLoadControllersFrom("controllers", application)
+
+// Lazy load controllers as they appear in the DOM (remember not to preload controllers in import map!)
+// import { lazyLoadControllersFrom } from "@hotwired/stimulus-loading"
+// lazyLoadControllersFrom("controllers", application)