diff --git a/courses/migrations/0005_auto_20180222_1911.py b/courses/migrations/0005_auto_20180222_1911.py
new file mode 100644
index 0000000..5ee4961
--- /dev/null
+++ b/courses/migrations/0005_auto_20180222_1911.py
@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.6 on 2018-02-22 19:11
+from __future__ import unicode_literals
+
+import django.contrib.postgres.fields
+from django.db import migrations, models
+import lms.tools
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('courses', '0004_auto_20180222_1756'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='lesson',
+            name='material_tokens',
+            field=django.contrib.postgres.fields.ArrayField(base_field=models.UUIDField(editable=False, verbose_name='Токен материала'), blank=True, default=lms.tools.get_empty_list, size=None, verbose_name='Материалы курса'),
+        ),
+    ]
diff --git a/courses/models.py b/courses/models.py
index 7d3f7ed..7785b4c 100755
--- a/courses/models.py
+++ b/courses/models.py
@@ -37,6 +37,7 @@ class Lesson(models.Model):
         models.UUIDField(verbose_name="Токен материала", editable=False),
         default=get_empty_list,
         verbose_name='Материалы курса',
+        blank=True
     )
     free = models.BooleanField(default=False, verbose_name='Привилегии для узла не будут проверяться')
     sort = models.SmallIntegerField(verbose_name='Поле сортировки')