diff --git a/seminar/migrations/0100_auto_20211129_2354.py b/seminar/migrations/0100_auto_20211129_2354.py
new file mode 100644
index 00000000..80906d4e
--- /dev/null
+++ b/seminar/migrations/0100_auto_20211129_2354.py
@@ -0,0 +1,19 @@
+# Generated by Django 2.2.24 on 2021-11-29 22:54
+
+from django.db import migrations, models
+import seminar.models.tvorba
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('seminar', '0099_auto_20210916_1509'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='cislo',
+            name='pdf',
+            field=models.FileField(blank=True, help_text='PDF čísla, které si mohou řešitelé stáhnout', null=True, storage=seminar.models.tvorba.OverwriteStorage(), upload_to=seminar.models.tvorba.cislo_pdf_filename, verbose_name='pdf'),
+        ),
+    ]
diff --git a/seminar/models/pomocne.py b/seminar/models/pomocne.py
index 16c46bf8..cb552a67 100644
--- a/seminar/models/pomocne.py
+++ b/seminar/models/pomocne.py
@@ -2,7 +2,6 @@
 import logging
 import os
 from django.db import models
-from django.core.files.storage import FileSystemStorage
 
 from .base import SeminarModelBase
 
diff --git a/seminar/models/tvorba.py b/seminar/models/tvorba.py
index 3e914efd..719375ff 100644
--- a/seminar/models/tvorba.py
+++ b/seminar/models/tvorba.py
@@ -12,6 +12,7 @@ from django.conf import settings
 from django.urls import reverse
 from django.core.cache import cache
 from django.core.exceptions import ObjectDoesNotExist, ValidationError
+from django.core.files.storage import FileSystemStorage
 from django.utils.text import get_valid_filename
 from django.utils.functional import cached_property