feat: 게시판 CRUD API 구현

Author: holly000

.gitignore

@@ -38,3 +38,4 @@ out/
 
 ### VS Code ###
 .vscode/
+.claude/

src/main/java/com/bootsignal/domain/user/entity/User.java

@@ -0,0 +1,27 @@
+package com.bootsignal.domain.user.entity;
+
+import com.bootsignal.global.entity.BaseEntity;
+import jakarta.persistence.*;
+import lombok.*;
+
+@Entity
+@Table(name = "users")
+@Getter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Builder
+public class User extends BaseEntity {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(nullable = false, unique = true)
+    private String email;
+
+    // OAuth2 가입 초기에 미설정 가능 → nullable
+    private String nickname;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private UserRole role;
+}

src/main/java/com/bootsignal/domain/user/entity/UserRole.java

@@ -0,0 +1,5 @@
+package com.bootsignal.domain.user.entity;
+
+public enum UserRole {
+    USER, ADMIN
+}

src/main/java/com/bootsignal/domain/user/repository/UserRepository.java

@@ -0,0 +1,10 @@
+package com.bootsignal.domain.user.repository;
+
+import com.bootsignal.domain.user.entity.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.util.Optional;
+
+public interface UserRepository extends JpaRepository<User, Long> {
+    Optional<User> findByEmail(String email);
+}