gorm manytomany many2many use go program

type RoleHasPermissionList struct {
	model.Roles
	Rolehaspermissions []CUS_Rolehaspermissions `json:"rolehaspermissions" gorm:"foreignkey:role_id; references:id"`
}

type CUS_Rolehaspermissions struct {
	PermissionId  int                 `json:"-"`
	RoleId        int                 `json:"-"`
	PermissinInfo model.Permission `gorm:"foreignkey:id; references:permission_id"`
}

func (CUS_Rolehaspermissions) TableName() string {
	return "RoleHasPermissions"
}

type FormaterResult struct {
	model.Roles
	Permission []model.Permission `json:"permission"`
}

func GetRoleList(c *gin.Context) serializer.Response {
	var req GetRoleListRequest
	c.ShouldBind(&req)

	var total int64
	var list []RoleHasPermissionList

	page := req.Page
	pageSize := req.PageSize

	model.DB.
		Scopes(util.Paginate(c, page, pageSize)).
		Preload("Rolehaspermissions.PermissinInfo").
		Find(&list).Offset(-1).Limit(-1).Count(&total)

	// 重新整理輸出格式
	var formater_result []FormaterResult
	for i, v := range list {
		formater_result = append(formater_result, FormaterResult{Roles: v.Roles})

		for _, v2 := range v.Rolehaspermissions {
			formater_result[i].Permission = append(formater_result[i].Permission, v2.PermissinInfo)
		}
	}

	return serializer.Response{
		Code:    0,
		Message: "成功",
		Data:    util.Pagination(c, page, pageSize, total, formater_result),
	}
}

    {   
        "id": 1,
        "name": "company",
        "display_name": "公司",
        "guard_name": "admin_api",
        "created_at": "2020-03-26 14:34:25",
        "updated_at": "2020-03-26 14:34:25",
        "permission": [
          {
            "id": 1,
            "name": "add company",
            "display_name": "add company",
            "guard_name": "admin_api",
            "created_at": "2020-03-26 14:34:25",
            "updated_at": "2020-03-26 14:34:25"
          },
          {
            "id": 2,
            "name": "edit company",
            "display_name": "edit company",
            "guard_name": "admin_api",
            "created_at": "2020-03-26 14:34:25",
            "updated_at": "2020-03-26 14:34:25"
          },
        ]
    },
    ...