added username length limit

api.js

@@ -58,7 +58,7 @@ api.post('/leaderboards/:category/:id', (req, res) => {
 		err: 'Invalid mode'
 	});
 	const username=req.body.username;
-	if((typeof username)!='string') return res.status(400).json({
+	if((typeof username)!='string' || username.length>100) return res.status(400).json({
 		ok: false,
 		err: 'Invalid username'
 	});