Initial commit

backend/src/main/java/com/smartoffice/user/UserRepository.java

@@ -0,0 +1,10 @@
+package com.smartoffice.user;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.util.Optional;
+
+public interface UserRepository extends JpaRepository<User, Long> {
+    Optional<User> findByUsername(String username);
+    boolean existsByUsername(String username);
+}