Update app.py

app.py

@@ -82,7 +82,7 @@ def predict(message, history):
         print("Switched to: {model}".format(model=model)) 
   
     response = client.chat.completions.create(
-        model=model,
+        model="gpt-3.5-turbo", # gpt-4 is temporarily disabled to save money
         messages= history_openai_format,
         temperature=0,
         stream=True)