function deliverBonus() public onlyOwner {
        require(bonusDeliverTime <= block.timestamp);
        for (uint i = 0; i<buyerList.length; i++){
            uint256 amount = buyerBonus[buyerList[i]];
            token.transfer(buyerList[i], amount);
            buyerBonus[buyerList[i]] = 0;
        }
    }