Make HostingBillLineAmount accept negative values

hosting/migrations/0056_auto_20191026_0454.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.4 on 2019-10-26 04:54
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('hosting', '0055_auto_20190701_1614'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='hostingbilllineitem',
+            name='amount',
+            field=models.IntegerField(),
+        ),
+    ]

hosting/models.py

@@ -466,7 +466,7 @@ class HostingBillLineItem(AssignPermissionsMixin, models.Model):
                                              on_delete=models.CASCADE)
     stripe_plan = models.ForeignKey(StripePlan, null=True,
                                     on_delete=models.CASCADE)
-    amount = models.PositiveSmallIntegerField()
+    amount = models.IntegerField()
     description = models.CharField(max_length=255)
     discountable = models.BooleanField()
     metadata = models.CharField(max_length=128)