finish review model

apps/review/models.py

@@ -1,7 +1,7 @@
 from django.contrib.contenttypes import fields as generic
+from django.core.validators import MinValueValidator, MaxValueValidator
 from django.db import models
 from django.utils.translation import gettext_lazy as _
-from django.core.validators import MinValueValidator, MaxValueValidator
 
 from utils.models import BaseAttributes
 
@@ -43,6 +43,7 @@ class Review(BaseAttributes):
     text = models.TextField(verbose_name=_('Text'))
     status = models.PositiveSmallIntegerField(choices=REVIEW_STATUSES, default=TO_INVESTIGATE)
     child = models.ForeignKey('self',
+                              blank=True, default=None, null=True,
                               on_delete=models.CASCADE,
                               verbose_name=_('Child review'))
     published_at = models.DateTimeField(verbose_name=_('Publish datetime'),