feat: 完善相关功能

commons/src/main/java/com/ivmiku/tutorial/response/AtNotifier.java

@@ -0,0 +1,14 @@
+package com.ivmiku.tutorial.response;
+
+import lombok.Data;
+
+/**
+ * 提醒用户实体
+ * @author Aurora
+ */
+@Data
+public class AtNotifier {
+    private String fromId;
+    private String toId;
+    private String postId;
+}