feat: 회원가입시 닉네임 중복 확인 기능 추가

src/main/java/com/taba/nimonaemo/member/controller/UserController.java

@@ -8,6 +8,8 @@
 import com.taba.nimonaemo.member.model.dto.response.ResponseSignupTokenDto;
 import com.taba.nimonaemo.member.service.MemberService;
 import com.taba.nimonaemo.member.service.SignupService;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.responses.ApiResponses;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import lombok.RequiredArgsConstructor;
 import org.springframework.web.bind.annotation.*;
@@ -72,6 +74,19 @@ public ResponseRefreshTokenDto refreshToken(HttpServletRequest request,
         return memberService.refreshToken(request, refreshToken);
     }
 
+    /**
+     * 닉네임 중복 확인
+     * @param nickname      닉네임
+     */
+    @ApiResponses(value = {
+            @ApiResponse(responseCode = "200", description = "중복되는 닉네임이 없습니다."),
+            @ApiResponse(responseCode = "500", description = "already.nickname")
+    })
+    @PostMapping("/signup/verify/{nickname}")
+    public void verifyNickname(@PathVariable("nickname") String nickname) {
+        signupService.checkAlreadyNickname(nickname);
+    }
+
 //    /**
 //     * 회원탈퇴
 //     * <p>회원은 바로 삭제되지 않고, 일정 기간 뒤에 삭제됩니다. 삭제시에도 개인 정보만 삭제됩니다.</p>

src/main/java/com/taba/nimonaemo/member/service/SignupService.java

@@ -72,7 +72,7 @@ private void checkAlreadyName(String name) {
         }
     }
 
-    private void checkAlreadyNickname(String nickname) {
+    public void checkAlreadyNickname(String nickname) {
         Optional<Member> alreadyMember = memberRepository.findByNickname(nickname);
         if (alreadyMember.isPresent()) {
             throw new AlreadyNicknameException();