message edit/update functionality

backend/database.py

@@ -80,10 +80,12 @@ class Message(Base):
     chat_id: Mapped[int] = mapped_column(ForeignKey("chats.id"))
     thread_id: Mapped[Optional[int]] = mapped_column(ForeignKey("threads.id"))
 
-    # Timestamp of this message
-    time: Mapped[int]
     # Identifier of the sender: user / system / user-$ID / agent-$ID
     sender: Mapped[str]
+    # Timestamp of this message
+    time: Mapped[int]
+    # Timestamp of this message's last edit
+    #last_edit: Mapped[int]
 
     # Predefined set of message types:
     # message, log, memory, file, note