feat: 회원가입 시 사용자 닉네임 입력 기능 구현

backend/core/src/main/java/com/rollthedice/backend/domain/member/dto/SignUpDto.java

@@ -0,0 +1,10 @@
+package com.rollthedice.backend.domain.member.dto;
+
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor
+@Getter
+public class SignUpDto {
+    private String nickname;
+}

backend/core/src/main/java/com/rollthedice/backend/domain/member/entity/Member.java

@@ -40,4 +40,8 @@ public Member update(String email, String imageUrl) {
     public void updateRefreshToken(String updateRefreshToken) {
         this.refreshToken = updateRefreshToken;
     }
+
+    public void updateNickname(String nickname) {
+        this.nickname = nickname;
+    }
 }

backend/core/src/main/java/com/rollthedice/backend/domain/member/service/MemberService.java

@@ -0,0 +1,18 @@
+package com.rollthedice.backend.domain.member.service;
+
+import com.rollthedice.backend.domain.member.dto.SignUpDto;
+import com.rollthedice.backend.domain.member.entity.Member;
+import com.rollthedice.backend.domain.member.query.AuthService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+@RequiredArgsConstructor
+@Service
+public class MemberService {
+    private final AuthService authService;
+
+    public void signUp(SignUpDto dto) {
+        Member member = authService.getMember();
+        member.updateNickname(dto.getNickname());
+    }
+}