요청
POST /activities/{activityId}/comments Authorization: <이곳에 JWT를 입력> { "comment": "COMMENT", // 댓글 내용 }
응답
{ "id": 1, "comment": "COMMENT", "userId": 101, "userName": "WRITER_USERNAME", "userImage": "PROFILE_IMAGE_URL", "userRole": "MEMBER", // "MEMBER", "CENTER". "createdDate": "2021-12-18T14:09:02", "updatedDate": "2021-12-18T14:09:02", }