Implement Transaction Class

[gra-m]

    private Map<Long, ITransaction> transactions;

@Override
    public ITransaction beginTransaction() {
        long threadId = Thread.currentThread().getId(); // If we know the thread id we can store the transaction
        ITransaction transaction = new Transaction();
        this.transactions.put(threadId, transaction); // now DB knows which transactions belong to this thread.. but if multiple wont work.
        return new Transaction();
    } ```