Add chatbot messages to history (I think)

app.py

@@ -18,3 +18,10 @@ if prompt := st.chat_input("What is up?"):
         st.markdown(prompt)
     # Add user message to chat history
     st.session_state.messages.append({"role": "user", "content": prompt})
+
+response = f"Echo: {prompt}"
+# Display assistant response in chat message container
+with st.chat_message("assistant"):
+    st.markdown(response)
+# Add assistant response to chat history
+st.session_state.messages.append({"role": "assistant", "content": response})