Update app.py

app.py

@@ -57,7 +57,7 @@ async def generater(message, history, temperature, top_p, top_k):
     main_path = os.path.join(current_dir, 'main')
     cmd = [
         main_path,
-        "-m", model_path+"/"+model_name,
+        "-m",os.path.join(model_path, model_name),
         "--prompt", prompt
     ]