added introductory prompt

backend.py

@@ -105,14 +105,13 @@ def handle_query(query_str: str,
                     ]
                 )
             index = build_index("data/chiarimento.txt")
-            
-                 
+                  
     
     else:
       
         
         # The index is already built, no need to rebuild it.
-        conversation: List[ChatMessage] = []
+        #conversation: List[ChatMessage] = []
         for user, assistant in chat_history:
             conversation.extend(
                 [