update Coupon

src/main/java/cn/seecoder/courselearning/po/Coupon.java

@@ -89,6 +89,7 @@ public class Coupon {
     }
 
     public Coupon(CouponVO couponVO) {
+        this.id = couponVO.getId();
         this.type = CouponType.valueOf(couponVO.getType());
         this.name = couponVO.getName();
         this.description = couponVO.getDescription();