Fix file uploading not working (ttl doesn't exist anymore)

src/controllers/FileController.ts

@@ -76,7 +76,7 @@ export default class FileController extends Controller {
             storage_type: 'local',
             storage_path: 'storage/uploads/' + slug,
             size: upload.size,
-            ttl: ttl,
+            expires_at: ttl <= 0 ? null : new Date(Date.now() + ttl * 1000),
         });
 
         await file.save();