add Dependencies and Routes classes

src/Dependencies.php

@@ -0,0 +1,29 @@
+<?php
+declare(strict_types=1);
+
+namespace NoteCat;
+
+use DI\Container;
+use Psr\Container\ContainerInterface;
+
+class Dependencies
+{
+    public static function createContainer(): Container
+    {
+        $container = new Container();
+
+        // Controllers
+        $container->set(HelloWorldController::class, function (ContainerInterface $c) {
+            return new HelloWorldController(
+                $c->get(HelloWorld::class)
+            );
+        });
+
+        // Services
+        $container->set(HelloWorld::class, function () {
+            return new HelloWorld();
+        });
+
+        return $container;
+    }
+}

src/HelloWorldController.php

@@ -0,0 +1,23 @@
+<?php
+declare(strict_types=1);
+
+namespace NoteCat;
+
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+
+class HelloWorldController
+{
+    private HelloWorld $hello;
+
+    public function __construct(HelloWorld $hello)
+    {
+        $this->hello = $hello;
+    }
+
+    public function hello(Request $request, Response $response): Response
+    {
+        $response->getBody()->write('<b>' . $this->hello->getHello() . "</b>\n");
+        return $response;
+    }
+}

src/Routes.php

@@ -0,0 +1,15 @@
+<?php
+declare(strict_types=1);
+
+namespace NoteCat;
+
+use NoteCat\HelloWorldController;
+use Slim\App;
+
+class Routes
+{
+    public static function setRoutes(App $app): void
+    {
+        $app->get('/', HelloWorldController::class . ':hello');
+    }
+}