send files with requests instead of serving the whole repertory in static

src/controllers/main.js

@@ -1,9 +1,14 @@
+const path = require('path');
 
 const mainController = {
   root: (req, res) => {
-    res.json({
-        message: "Hello, World!",
-    });
+    res.sendFile(path.resolve(__dirname + '/../public/index.html'));
+  },
+  style: (req, res) => {
+    res.sendFile(path.resolve(__dirname + '/../public/style.css'));
+  },
+  script: (req, res) => {
+    res.sendFile(path.resolve(__dirname + '/../public/script.js'));
   }
 };