Update server.js

server.js

@@ -18,7 +18,7 @@ app.post('/chat', async (req, res) => {
         ];
 
         const response = await axios.post(targetUrl, {
-            model: req.body.model,
+            model: 'gemini-1.5-pro-latest',
             messages: messages
         }, {
             headers: {