Add index.html with Stimulus hello controller

assets/esbuild.config.mjs

@@ -0,0 +1,32 @@
+import * as esbuild from 'esbuild';
+import { stimulusPlugin } from 'esbuild-plugin-stimulus';
+
+let minify = false;
+let sourcemap = true;
+let watch = true;
+
+if (process.env.NODE_ENV === 'production') {
+  minify = true;
+  sourcemap = false;
+  watch = false;
+}
+
+const config = {
+  bundle: true,
+  entryPoints: ['./assets/js/app.js'],
+  minify,
+  outdir: './public/build',
+  plugins: [stimulusPlugin()],
+  sourcemap,
+}
+
+if (watch) {
+  let context = await esbuild.context({
+    ...config,
+    logLevel: 'info',
+  });
+
+  await context.watch()
+} else {
+  esbuild.build(config)
+}

assets/js/app.js

@@ -0,0 +1,5 @@
+import { Application } from "@hotwired/stimulus";
+import { definitions } from "stimulus:./controllers";
+
+const app = Application.start();
+app.load(definitions);

assets/js/controllers/hello_controller.js

@@ -0,0 +1,7 @@
+import { Controller } from "@hotwired/stimulus";
+
+export default class extends Controller {
+  connect() {
+    console.log("hello#connect");
+  }
+}