每15分钟 执行schedule

System.schedule('审批历史15分刷新', '0 0 * * * ?', newProjectApprovalScheduler());    

System.schedule('审批历史15分刷新', '0 15 * * * ?', newProjectApprovalScheduler());                                

System.schedule('审批历史30分刷新', '0 30 * * * ?', newProjectApprovalScheduler());

System.schedule('审批历史45分刷新', '0 45 * * * ?', newProjectApprovalScheduler());