Refactor 4 with bugfixes

server/src/app.ts

@@ -0,0 +1,14 @@
+import express from 'express';
+import cors from 'cors';
+import { registerRoutes } from './routes';
+
+export function createApp(): express.Express {
+  const app = express();
+
+  app.use(cors());
+  app.use(express.json());
+
+  registerRoutes(app);
+
+  return app;
+}