Help: where i can find this?

hey there
i was trying to sreach a simple platform
but i cant find anything
and its something really simple, i need something like a guest book, but that all message must be aproved bya moderator, does anybody knows some platform that do that?
i search a lot of open source guest books and i cant find no one that requires moderation for the messages
if someone knows where i can find one
i will apreciate it