FEAT: deleteRoom endpoint and ResponseEntity usage

src/main/java/com/mallardromain/hotel/config/DatabaseSeeder.java

@@ -18,9 +18,12 @@ public class DatabaseSeeder {
             if (userRepository.count() == 0) {
                 User testUser1 = new User("test1", passwordEncoder.encode("password1"));
                 User testUser2 = new User("test2", passwordEncoder.encode("password2"));
-            
+                User adminUser1 = new User("admin1", passwordEncoder.encode("password1"));
+                adminUser1.setRole("ADMIN");
+
                 userRepository.save(testUser1);
                 userRepository.save(testUser2);
+                userRepository.save(adminUser1);
             }
         };
     }