public void AddExtraCards()
    {
        if (paused)
        {
            return;
        }

        if (DataManager.Instance.Coins < costForAddExtraCards)
        {
            // TODO: Add method to purchase coins.
            return;
        }

        DataManager.Instance.Coins -= costForAddExtraCards;

        for (int i = 0; i < extraCardsPowerup; i++)
        {
            Card card = deck.CreateNewCard();
            card.Rank = (CardRank)Random.Range(0, System.Enum.GetNames(typeof(CardRank)).Length);
            card.Suit = (CardSuit)Random.Range(0, System.Enum.GetNames(typeof(CardSuit)).Length);
            deck.AddCardOnTop(card);
            card.IsGeneratedCard = true;
        }
    }