Reset task field IDs to null after task update

src/main/java/cz/muni/fi/pv168/project/db/task/TaskDao.java

@@ -197,12 +197,15 @@ public class TaskDao implements DataAccessObject<Task> {
 
     private void addTaskFieldsToDaos(Task entity) {
         for (var subtask : entity.getSubTasks()) {
+            subtask.setId(null);
             subTaskDao.addEntityFor(entity.getId(), subtask);
         }
         for (var dependency : entity.getDependencyTasks()) {
+            dependency.setId(null);
             dependencyDao.addAssociationFor(entity.getId(), dependency.getId());
         }
         for (var category : entity.getCategories()) {
+            category.setId(null);
             taskCategoryDao.addAssociationFor(entity.getId(), category.getId());
         }
     }