function initializeMilestones(uint256[] _bonus, uint256[] _total) public onlyOwner {
        require(_bonus.length > 0 && _bonus.length == _total.length);
        for(uint256 i = 0; i < _bonus.length; i++) {
            milestones[i] = Milestone({ total: _total[i], bonus: _bonus[i] });
        }
        milestoneCount = _bonus.length;
        initialized = true;
    }