chore: Set dataset date when adding to the repository

src/main/java/de/uni_passau/fim/PADAS/group3/DataDash/model/DatasetService.java

@@ -1,5 +1,6 @@
 package de.uni_passau.fim.PADAS.group3.DataDash.model;
 
+import java.time.LocalDate;
 import java.util.List;
 import java.util.Optional;
 import java.util.UUID;
@@ -26,6 +27,7 @@ public class DatasetService {
     }
 
     public void addDataset(Dataset dataset) {
+        dataset.setDate(LocalDate.now());
         datasetRepository.save(dataset);
     }