add postgre integration to store chat history in database

app.py

@@ -3,34 +3,42 @@ from langchain_community.llms import HuggingFaceTextGenInference
 import os
 from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler
 from langchain.schema import StrOutputParser
+from datetime import datetime
 
 from custom_llm import CustomLLM, custom_chain_with_history
 
-
-API_TOKEN = os.getenv('HF_INFER_API')
-
-
 from typing import Optional
 
 from langchain.prompts import ChatPromptTemplate, MessagesPlaceholder
-from langchain_community.chat_models import ChatAnthropic
 from langchain_core.chat_history import BaseChatMessageHistory
-from langchain.memory import ConversationBufferMemory
-from langchain_core.runnables.history import RunnableWithMessageHistory
+from langchain.memory import ConversationBufferMemory, PostgresChatMessageHistory
+
+
+
+
+API_TOKEN = os.getenv('HF_INFER_API')
+POSTGRE_URL = os.environ('POSTGRE_URL')
+
 
 
 if 'memory' not in st.session_state:
-    st.session_state['memory'] = ConversationBufferMemory(return_messages=True)
+    # st.session_state['memory'] = ConversationBufferMemory(return_messages=True)
+    
+    st.session_state.memory = PostgresChatMessageHistory(connection_string=POSTGRE_URL, session_id=str(datetime.timestamp(datetime.now())))
 
 if 'chain' not in st.session_state:
-    st.session_state['chain'] = custom_chain_with_history(llm=CustomLLM(repo_id="mistralai/Mixtral-8x7B-Instruct-v0.1", model_type='text-generation', api_token=API_TOKEN, stop=["\n<|","<|"]), memory=st.session_state.memory)
+    st.session_state['chain'] = custom_chain_with_history(
+        llm=CustomLLM(repo_id="mistralai/Mixtral-8x7B-Instruct-v0.1", model_type='text-generation', api_token=API_TOKEN, stop=["\n<|","<|"]), 
+        # memory=st.session_state.memory.chat_memory,
+        memory=st.session_state.memory
+    )
 
 st.title("Chat With Me")
 st.subheader("by Jonathan Jordan")
 
 # Initialize chat history
 if "messages" not in st.session_state:
-    st.session_state.messages = []
+    st.session_state.messages = [{"role":"assistant", "content":"Hello, My name is Jonathan Jordan. You can call me Jojo. How can I help you today?"}]
 
 # Display chat messages from history on app rerun
 for message in st.session_state.messages: