modified Backend

[Xiaoyang-Gu]

Signed-off-by: 顾晓阳 guxiaoyang@bupt.edu.cn

Fixes : [#96 ]

Description :

• Add PolicyList for policy get/post.

• Modified for edit/add/delete.

Screenshot of changes :

Please ensure Checkmark the following :

• [x] - Tested Localy
• [x] - Checked in IE11 and Firefox
• [ ] - Checked in mobile
• [x] - Backend work
• [ ] - Frontend work
• [x] - Bug Fixes
• [x] - Enhancements

[Xiaoyang-Gu]

@hsluoyz @BetaCat0 @GopherJ Please review.

[hsluoyz]

@BetaCat0 @nodece