refactor: store all known as map for access

routes/login_page.go

@@ -135,7 +135,8 @@ func createRoomHandler(templateFs *embed.FS,
 			PasswordHash:   r.PostFormValue("roomPassword"), // TODO hash the password, not to store
 			AdminIds:       []rooms.PersonId{person.Id},
 			Paricipants:    []rooms.PersonId{person.Id},
-			AllKnownPeople: []rooms.Person{person},
+			AllKnownPeople: map[rooms.PersonId]rooms.Person{
+				person.Id: person},
 		}
 		err = roomsM.Save(newRoom)
 		if err != nil {
@@ -247,7 +248,7 @@ func joinRoomHandler(templateFs *embed.FS,
 			err := roomsM.Update(r.Context(), room.Name, func(fromRoom rooms.Room) (toRoom rooms.Room) {
 				log.Printf("/login/join about to modify room %+v", fromRoom)
 				toRoom = fromRoom
-				toRoom.AllKnownPeople = append(toRoom.AllKnownPeople, person)
+				toRoom.AllKnownPeople[person.Id] =  person
 				log.Printf("/login/join will save %+v", toRoom)
 				return toRoom
 			})