1. 增加借款方可还款/可提前还款的payback列表服务
        可还款 yes IPayBackService public List<PayBack>
findBorrowerCanBeRepayedPayBacks();
        可提前 yes IPayBackService public List<PayBack>
findBorrowerCanBeRepayedInAdvancePayBacks();
9. 提供一个服务判断某一个payback
                                    是否可支付   yes   IPayBackService public
boolean canRepay(Integer payBackId);
                                    是否可申请提前 yes IPayBackService public
boolean canRepayInAdvance(Integer payBackId);