Add schema and DAO for cursors in cloudsql (#370)

* Add schema for Cursor

* Add CursorDao and CursorDaoTest

* Fix comment on getTld

* Change tld column to scope

* Fix cursorTime to be converted to DateTime internally and other small fixes

* Add a CursorType enum and a createGlobal constructor for Cursor

* Rename flyway file

* Use cursorType from common/Cursor.java and add null checks

db/src/main/resources/sql/flyway/V11__create_cursor.sql

@@ -0,0 +1,21 @@
+-- Copyright 2019 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 "Cursor" (
+       scope text not null,
+        type text not null,
+        cursor_time timestamptz not null,
+        last_update_time timestamptz not null,
+        primary key (scope, type)
+    );

db/src/main/resources/sql/schema/db-schema.sql.generated

@@ -26,6 +26,14 @@
         primary key (revision_id)
     );
 
+    create table "Cursor" (
+       scope text not null,
+        type text not null,
+        cursor_time timestamptz not null,
+        last_update_time timestamptz not null,
+        primary key (scope, type)
+    );
+
     create table "DelegationSignerData" (
        key_tag int4 not null,
         algorithm int4 not null,

db/src/main/resources/sql/schema/nomulus.golden.sql

@@ -61,6 +61,18 @@ CREATE SEQUENCE public."ClaimsList_revision_id_seq"
 ALTER SEQUENCE public."ClaimsList_revision_id_seq" OWNED BY public."ClaimsList".revision_id;
 
 
+--
+-- Name: Cursor; Type: TABLE; Schema: public; Owner: -
+--
+
+CREATE TABLE public."Cursor" (
+    scope text NOT NULL,
+    type text NOT NULL,
+    cursor_time timestamp with time zone NOT NULL,
+    last_update_time timestamp with time zone NOT NULL
+);
+
+
 --
 -- Name: PremiumEntry; Type: TABLE; Schema: public; Owner: -
 --
@@ -228,6 +240,14 @@ ALTER TABLE ONLY public."ClaimsList"
     ADD CONSTRAINT "ClaimsList_pkey" PRIMARY KEY (revision_id);
 
 
+--
+-- Name: Cursor Cursor_pkey; Type: CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public."Cursor"
+    ADD CONSTRAINT "Cursor_pkey" PRIMARY KEY (scope, type);
+
+
 --
 -- Name: PremiumEntry PremiumEntry_pkey; Type: CONSTRAINT; Schema: public; Owner: -
 --