billing: Add coupons.

zilencer/migrations/0012_coupon.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.14 on 2018-08-23 05:40
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('zilencer', '0011_customer_has_billing_relationship'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Coupon',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('percent_off', models.SmallIntegerField(unique=True)),
+                ('stripe_coupon_id', models.CharField(max_length=255, unique=True)),
+            ],
+        ),
+    ]