added memory

backend.py

@@ -115,9 +115,9 @@ def handle_query(query_str, chat_history) -> Iterator[str]:
         response = chat_engine.stream_chat(query_str)
         #response = chat_engine.chat(query_str)
         for token in response.response_gen:
-          if not token.startswith("system:") and not token.startswith("user:"):
+          #if not token.startswith("system:") and not token.startswith("user:"):
           
-            outputs.append(str(token))
+            outputs.append(token)
             print(f"Generated token: {token}")
             yield "".join(outputs)