[230319] 결제완료 command 개발

- 각 폴더 구조 생성
- 도메인 Event 구조 생성
- kafka message sender 테스트까지 확인
- 결제 완료 예시 application service

payment-command/src/main/java/com/example/user/domain/Cash.java

@@ -0,0 +1,43 @@
+package com.example.user.domain;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import java.util.UUID;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.NoArgsConstructor;
+import org.springframework.data.annotation.CreatedDate;
+import org.springframework.data.annotation.LastModifiedDate;
+
+@Entity
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+public class Cash {
+
+    @Id
+    private String id;
+
+    private BigDecimal amount;
+
+    @ManyToOne
+    @JoinColumn
+    private User user;
+
+    @CreatedDate
+    private LocalDateTime createdAt;
+
+    @LastModifiedDate
+    private LocalDateTime updatedAt;
+
+    public String getId() {
+        return id;
+    }
+
+    public static Cash of(BigDecimal amount, User user) {
+        return new Cash(UUID.fromString("cash").toString(), amount, user, null, null);
+    }
+}