added introductory prompt

backend.py

@@ -146,7 +146,7 @@ def handle_query(query_str: str,
                 print(f"Generated token: {token}")
                 
                 #yield "".join(outputs)
-                yield CompletionResponse(text=outputs, delta=token)
+                yield CompletionResponse(text=''.join(outputs), delta=token)
 
         """if sources:
             sources_str = ", ".join(sources)