Save user's configuration to otherwise unused field ``full_name`` in passwd
    file.

def save_user_config(username, conf_dict, path=settings.LOGIN_FILE):
    """
    Save user's configuration to otherwise unused field ``full_name`` in passwd
    file.
    """
    users = load_users(path=path)
    users[username]["full_name"] = _encode_config(conf_dict)
    save_users(users, path=path)