fix testRegister_success

Change-Id: Ia125fff2481df66233819187a25de74f82ad34c3
diff --git a/src/main/java/com/g9/g9backend/pojo/Reward.java b/src/main/java/com/g9/g9backend/pojo/Reward.java
index 91e376d..5812284 100644
--- a/src/main/java/com/g9/g9backend/pojo/Reward.java
+++ b/src/main/java/com/g9/g9backend/pojo/Reward.java
@@ -1,5 +1,6 @@
 package com.g9.g9backend.pojo;
 
+import com.baomidou.mybatisplus.annotation.IdType;
 import com.baomidou.mybatisplus.annotation.TableId;
 import lombok.*;
 
@@ -15,7 +16,7 @@
 @NoArgsConstructor
 public class Reward {
 
-    @TableId
+    @TableId(type = IdType.AUTO)
     private int rewardId;
 
     private String rewardName;