Update app.py

app.py

@@ -26,7 +26,7 @@ def setup_auth():
 
 class LlamaDemo:
     def __init__(self):
-        self.model_name = "meta-llama/Llama-2-70b-chat"
+        self.model_name = "meta-llama/Llama-2-7b-chat"
         self._model = None
         self._tokenizer = None