Resolve "CSVImport blocks celery workers with haystack tasks"

Mitigates #37 (closed)

aleksis/apps/csv_import/util/process.py

@@ -3,6 +3,7 @@ from typing import Optional
 
 from django.contrib import messages
 from django.core.exceptions import ValidationError
+from django.db import transaction
 from django.utils.translation import gettext as _
 
 import pandas
@@ -23,6 +24,7 @@ from aleksis.core.util.celery_progress import ProgressRecorder
 from ..models import ImportJob
 
 
+@transaction.atomic
 def import_csv(
     import_job: ImportJob,
     recorder: Optional[ProgressRecorder] = None,