Update app.py with current date

app.py

@@ -3,6 +3,7 @@ from openai import OpenAI
 from typing import Iterator
 import os
 from phoenix.otel import register
+from datetime import datetime
 
 tracer_provider = register(
   project_name=st.secrets['PHOENIX_PROJECT_NAME'],
@@ -30,7 +31,8 @@ if "openai_model" not in st.session_state:
     st.session_state["openai_model"] = st.secrets['MODEL']
 
 if "messages" not in st.session_state:
-    st.session_state.messages = []
+    current_date = datetime.now().strftime("%Y-%m-%d")
+    st.session_state.messages = [{"role": "system", "content": f"現在的日期: {current_date}"}]
 
 for message in st.session_state.messages:
     with st.chat_message(message["role"]):