How do I save leaderboard stats?

I am making a hide and seek game and I need to figure out how to save wins. Here is a basic leaderboard script I used.

    local function onPlayerJoin(player)

        local leaderstats = Instance.new("Folder")
        leaderstats.Name = "leaderstats"
        leaderstats.Parent = player

        local gold = Instance.new("IntValue")
        gold.Name = "Gold"
        gold.Value = 0
        gold.Parent = leaderstats

    end

    game.Players.PlayerAdded:Connect(onPlayerJoin)

It only works for the session in-game, but when I leave it doesn't save.