Add SQL schema for GracePeriod (#709)

* Add SQL schema for GracePeriod

* Remove the join table

* Add a domainRepoId in GracePeriod

* Move the clone logic to GracePeriod

* Rebase on HEAD

db/src/main/resources/sql/flyway/V45__add_grace_period_table.sql

@@ -0,0 +1,41 @@
+-- Copyright 2020 The Nomulus Authors. All Rights Reserved.
+--
+-- Licensed under the Apache License, Version 2.0 (the "License");
+-- you may not use this file except in compliance with the License.
+-- You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+
+create table "GracePeriod" (
+    id  bigserial not null,
+    billing_event_id int8,
+    billing_recurrence_id int8,
+    registrar_id text not null,
+    domain_repo_id text not null,
+    expiration_time timestamptz not null,
+    type text not null,
+    primary key (id)
+);
+
+alter table if exists "GracePeriod"
+   add constraint FK2mys4hojm6ev2g9tmy5aq6m7g
+   foreign key (domain_repo_id)
+   references "Domain";
+
+alter table if exists "GracePeriod"
+   add constraint fk_grace_period_billing_event_id
+   foreign key (billing_event_id)
+   references "BillingEvent";
+
+alter table if exists "GracePeriod"
+   add constraint fk_grace_period_billing_recurrence_id
+   foreign key (billing_recurrence_id)
+   references "BillingRecurrence";
+
+create index IDXj1mtx98ndgbtb1bkekahms18w on "GracePeriod" (domain_repo_id);