HttpTsec_10.scala

object UserStore {
def apply(user: UsernamePasswordCredentials, users: UsernamePasswordCredentials*): IO[UserStore] =
  for {
    userList <- (user +: users)
      .map(u => UserStore.newUser(u.username, u.password))
      .toList
      .sequence
    users <- Ref.of[IO, Map[UserId, User]](userList.map(u => u.id -> u).toMap)
  } yield
    new UserStore(
      (id: UserId) => OptionT(users.get.map(_.get(id))),
      usr => users.get.map(_.values.toList).flatMap(validateUser(usr)(_))
    )
}