회원가입 API

sequenceDiagram
User->>Client : 회원 가입 요청
Client -->>API Server : POST /api/members
 API Server ->> Member : 계정 생성 요청
Member ->> Member : 중복 검사
Member ->> Member : 계정 생성
Member -->> API Server : 응답 또는 예외
API Server-->>Client : API 응답
Client -->> User : 로그인 페이지 리다이렉션

Body :{
	username : ${username}
	email : ${email}
	phoneNumber : ${phoneNumber}
	password : ${password}
}

Response: {
	id : ${id}
}