Add rate to the primary key of ft_billing.

Use the primary key constraint in the upsert statement (easier to read than listing all the columns)

app/dao/fact_billing_dao.py

@@ -222,13 +222,7 @@ def update_fact_billing(data, process_day):
     )
 
     stmt = stmt.on_conflict_do_update(
-        index_elements=[table.c.bst_date,
-                        table.c.template_id,
-                        table.c.service_id,
-                        table.c.provider,
-                        table.c.rate_multiplier,
-                        table.c.notification_type,
-                        table.c.international],
+        constraint="ft_billing_pkey",
         set_={"notifications_sent": stmt.excluded.notifications_sent,
               "billable_units": stmt.excluded.billable_units
               }

migrations/versions/0191_ft_billing_pkey.py

@@ -0,0 +1,29 @@
+"""
+
+Revision ID: 0191_ft_billing_pkey
+Revises: 0190_another_letter_org
+Create Date: 2018-05-21 14:24:27.229511
+
+"""
+from alembic import op
+
+revision = '0191_ft_billing_pkey'
+down_revision = '0190_another_letter_org'
+
+
+def upgrade():
+    op.get_bind()
+    op.execute("ALTER TABLE ft_billing DROP CONSTRAINT ft_billing_pkey")
+    sql = """ALTER TABLE ft_billing ADD CONSTRAINT 
+    ft_billing_pkey PRIMARY KEY 
+    (bst_date, template_id, service_id, rate_multiplier, provider, notification_type, international, rate)"""
+    op.execute(sql)
+
+
+def downgrade():
+    op.get_bind()
+    op.execute("ALTER TABLE ft_billing DROP CONSTRAINT ft_billing_pkey")
+    sql = """ALTER TABLE ft_billing ADD CONSTRAINT 
+    ft_billing_pkey PRIMARY KEY 
+    (bst_date, template_id, service_id, rate_multiplier, provider, notification_type, international)"""
+    op.execute(sql)