diff --git a/nummi/main/migrations/0009_alter_invoice_file_alter_invoice_transaction_and_more.py b/nummi/main/migrations/0009_alter_invoice_file_alter_invoice_transaction_and_more.py
new file mode 100644
index 0000000..a1a64ac
--- /dev/null
+++ b/nummi/main/migrations/0009_alter_invoice_file_alter_invoice_transaction_and_more.py
@@ -0,0 +1,47 @@
+# Generated by Django 4.1.4 on 2022-12-28 11:20
+
+import django.core.validators
+from django.db import migrations, models
+import django.db.models.deletion
+import main.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("main", "0008_auto_20221221_1657"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="invoice",
+            name="file",
+            field=models.FileField(
+                max_length=128,
+                upload_to=main.models.invoice_path,
+                validators=[django.core.validators.FileExtensionValidator(["pdf"])],
+                verbose_name="Fichier",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="invoice",
+            name="transaction",
+            field=models.ForeignKey(
+                editable=False,
+                on_delete=django.db.models.deletion.CASCADE,
+                to="main.transaction",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="snapshot",
+            name="file",
+            field=models.FileField(
+                blank=True,
+                default="",
+                max_length=256,
+                upload_to=main.models.snapshot_path,
+                validators=[django.core.validators.FileExtensionValidator(["pdf"])],
+                verbose_name="Fichier",
+            ),
+        ),
+    ]
diff --git a/nummi/main/models.py b/nummi/main/models.py
index b293099..58a88a5 100644
--- a/nummi/main/models.py
+++ b/nummi/main/models.py
@@ -196,6 +196,7 @@ class Snapshot(models.Model):
         verbose_name=_("File"),
         max_length=256,
         blank=True,
+        default="",
     )
 
     def __str__(self):