#4 added additional route for get request to shortUrl

backend/src/index.ts

-import express, {Express} from 'express';
+import express, {Express, Request, Response} from 'express';
 import {linksRouter} from './routes/links.router';
-import {connectToDatabase} from './services/database.service';
+import {collections, connectToDatabase} from './services/database.service';
 
 const app: Express = express();
 app.use(express.json());
@@ -12,6 +12,25 @@ connectToDatabase()
     app.listen(process.env.PORT, () => {
       console.log(`Server started at http://localhost:${process.env.PORT}`);
     });
+
+    app.get('/:shortUrl', async (req: Request, res: Response) => {
+      try {
+        const shortUrl = req.params.shortUrl;
+
+        const link = await collections.links?.findOne({
+          shortUrl: `${process.env.BASE_URL}/${shortUrl}`,
+        });
+
+        if (link) {
+          res.status(301).redirect(link.originalUrl);
+        } else {
+          res.status(404).send('Not found');
+        }
+      } catch (err: unknown) {
+        const error = err as Error;
+        console.log(error);
+      }
+    });
   })
   .catch((error: Error) => {
     console.log('Database connection failed');