void dodaj_kontakt(node **head){
    char datoteka[20];
    cout << "Naziv datoteke?" << endl;
    cin >> datoteka;
    fstream file;
    file.open(datoteka, ios::binary | ios::out | ios::app);
    node *current;
    node *new_contact = new node;

    cin.ignore();
    cout << "Unesi ime: ";
    getline(cin, new_contact->name);
    file << "ime: " << new_contact->name << endl;
    cout << "Unesi e-mail: ";
    getline(cin, new_contact->email);
    file << "email: " << new_contact->email;
    new_contact->next = NULL;

    if(!*head)
    {
        *head = new_contact;
        return;
    }
    for(current = *head; current->next; current = current->next);
    current->next = new_contact;
}