LIL-271. Update AuthorBalance model

apps/payment/models.py

@@ -13,14 +13,19 @@ User = get_user_model()
 
 
 class AuthorBalance(models.Model):
+    IN = 0
+    OUT = 1
     TYPE_CHOICES = (
-        (0, 'In'),
-        (1, 'Out'),
+        (IN, 'In'),
+        (OUT, 'Out'),
     )
+    PENDING = 0
+    ACCEPTED = 1
+    DECLINED = 2
     STATUS_CHOICES = (
-        (0, 'Pending'),
-        (1, 'Accepted'),
-        (2, 'Declined'),
+        (PENDINNG, 'Pending'),
+        (ACCEPTED, 'Accepted'),
+        (DECLINED, 'Declined'),
     )
     author = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name='Автор',
                                null=True, blank=True, related_name='balances')