Add mib_reference field to Payment model and set default ordering by created_at

billing/models.py

@@ -16,6 +16,7 @@ class Payment(models.Model):
         ("TRANSFER", "Transfer"),
     ]
     id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    mib_reference = models.CharField(default="", null=True, blank=True)
     number_of_months = models.IntegerField()
     amount = models.FloatField()
     paid = models.BooleanField(default=False)
@@ -30,6 +31,9 @@ class Payment(models.Model):
     def __str__(self):
         return f"Payment by {self.user}"
 
+    class Meta:
+        ordering = ["-created_at"]
+
 
 class BillFormula(models.Model):
     formula = models.CharField(max_length=255)