Notice 도메인 개선

src/main/java/com/yapp/artie/domain/notice/domain/Notice.java

@@ -6,6 +6,8 @@
 import javax.persistence.GeneratedValue;
 import javax.persistence.GenerationType;
 import javax.persistence.Id;
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
@@ -20,12 +22,14 @@ public class Notice {
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Long id;
 
+  @NotBlank
   @Column(nullable = false)
   private String title;
 
   @Column(columnDefinition = "text")
   private String contents;
 
+  @NotNull
   @Column(nullable = false, updatable = false)
   @CreatedDate
   private LocalDateTime createdAt;