fix : ErrorCode 정의

- http 상태 코드
- 에러 메세지

src/main/java/com/prgrms/catchtable/common/exception/ErrorCode.java

@@ -0,0 +1,14 @@
+package com.prgrms.catchtable.common.exception;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.HttpStatus;
+
+@Getter
+@RequiredArgsConstructor
+public enum ErrorCode {
+    NOT_EXIST_MEMBER(HttpStatus.BAD_REQUEST, "존재하지 않는 아이디입니다.");
+
+    private final HttpStatus httpStatus;
+    private final String message;
+}