#27 -- fix out of memory and transactional removing

src/main/java/ru/ulstu/extractor/service/CommitService.java

@@ -10,6 +10,7 @@ import org.springframework.stereotype.Service;
 import ru.ulstu.extractor.model.Commit;
 import ru.ulstu.extractor.repository.CommitRepository;
 
+import javax.transaction.Transactional;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -39,6 +40,7 @@ public class CommitService {
                 }).collect(Collectors.toList());
     }
 
+    @Transactional
     public void deleteWithEmptyIds() {
         commitRepository.deleteByBranchIsNull();
     }