Add domain-specific history fields to DomainHistory objects (#794)

* Add domain-specific history fields to DomainHistory objects

* Add javadoc for Hibernate-only methods

* V52 -> V54

* Use only a single DomainTransactionRecord table

* Add nullables and fix up a comment

* V54 -> V55

* Regenerate db schema

* Regen SQL file

db/src/main/resources/sql/flyway/V55__domain_history_fields.sql

@@ -0,0 +1,34 @@
+-- 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.
+
+
+ALTER TABLE "DomainHistory" ADD COLUMN history_other_registrar_id text;
+ALTER TABLE "DomainHistory" ADD COLUMN history_period_unit text;
+ALTER TABLE "DomainHistory" ADD COLUMN history_period_value int4;
+
+CREATE TABLE "DomainTransactionRecord" (
+   id bigserial NOT NULL,
+    report_amount int4 NOT NULL,
+    report_field text NOT NULL,
+    reporting_time timestamptz NOT NULL,
+    tld text NOT NULL,
+    domain_repo_id text,
+    history_revision_id int8,
+    PRIMARY KEY (id)
+);
+
+ALTER TABLE IF EXISTS "DomainTransactionRecord"
+   ADD CONSTRAINT FKcjqe54u72kha71vkibvxhjye7
+   FOREIGN KEY (domain_repo_id, history_revision_id)
+   REFERENCES "DomainHistory";