Set date field for LiveLesson unique

apps/school/migrations/0016_auto_20180429_0818.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.0.4 on 2018-04-29 05:18
+
+from django.db import migrations, models
+import django.utils.timezone
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('school', '0015_auto_20180424_1825'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='livelesson',
+            name='date',
+            field=models.DateField(default=django.utils.timezone.now, unique=True),
+        ),
+    ]

apps/school/models.py

@@ -94,7 +94,7 @@ class LiveLesson(BaseModel, DeactivatedMixin):
     title = models.CharField('Название урока', max_length=100)
     short_description = models.TextField('Краткое описание урока')
     stream = models.URLField('Ссылка на VIMEO', default='', blank=True)
-    date = models.DateField(default=now)
+    date = models.DateField(default=now, unique=True)
     cover = models.ForeignKey(
         ImageObject,
         related_name='livelesson_covers',