跨App模块进行外键的关联：

格式应当为：模块名称.Model名称

# sysmanage.py 
class WorkOreder(model.Model):
    pass

# WorkFlow.py
class FlowList(model.Model):
    work_name = models.ForeignKey("sysmanage.WorkOrder", on_delete=models.CASCADE, verbose_name="流程类型",related_name="work")

跨App模块进行外键的关联