billing: Apply a flat discount for self hosted plans.

corporate/migrations/0031_customer_flat_discount_and_more.py

@@ -0,0 +1,22 @@
+# Generated by Django 4.2.8 on 2023-12-19 12:24
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("corporate", "0030_alter_zulipsponsorshiprequest_requested_plan"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="customer",
+            name="flat_discount",
+            field=models.IntegerField(default=2000),
+        ),
+        migrations.AddField(
+            model_name="customer",
+            name="flat_discounted_months",
+            field=models.IntegerField(default=0),
+        ),
+    ]