fix: track daily experience to prevent abuse

src/main/java/com/openisle/repository/ExperienceLogRepository.java

@@ -0,0 +1,12 @@
+package com.openisle.repository;
+
+import com.openisle.model.ExperienceLog;
+import com.openisle.model.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.time.LocalDate;
+import java.util.Optional;
+
+public interface ExperienceLogRepository extends JpaRepository<ExperienceLog, Long> {
+    Optional<ExperienceLog> findByUserAndLogDate(User user, LocalDate logDate);
+}