定时任务里面ExecJob类型的函数怎么调用数据库，直接调用service里面的方法提示重复引入

### Reproduction link

[https://github.com/go-admin-team/go-admin/issues](https://github.com/go-admin-team/go-admin/issues)

### Steps to reproduce

无

### What is expected?

调用数据库

### What is actually happening?

调用数据库

| Environment | Info |
| --- | --- |
| go-admin | undefined |
| Go | 1.9 |
| System | mac |
| Browser | 谷歌 |