Allow null for start & end date of SchoolPayment

apps/payment/migrations/0010_auto_20180227_0933.py

@@ -0,0 +1,23 @@
+# Generated by Django 2.0.2 on 2018-02-27 09:33
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('payment', '0009_auto_20180222_0955'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='schoolpayment',
+            name='date_end',
+            field=models.DateField(blank=True, null=True, verbose_name='Дата окончания подписки'),
+        ),
+        migrations.AlterField(
+            model_name='schoolpayment',
+            name='date_start',
+            field=models.DateField(blank=True, null=True, verbose_name='Дата начала подписки'),
+        ),
+    ]

apps/payment/models.py

@@ -92,8 +92,8 @@ class CoursePayment(Payment):
 
 class SchoolPayment(Payment):
     weekdays = ArrayField(models.IntegerField(), size=7, verbose_name='Дни недели')
-    date_start = models.DateField('Дата начала подписки')
+    date_start = models.DateField('Дата начала подписки', null=True, blank=True)
-    date_end = models.DateField('Дата окончания подписки')
+    date_end = models.DateField('Дата окончания подписки', null=True, blank=True)
 
     class Meta:
         verbose_name = 'Платеж за школу'