Introduce namespace limits table

The two initial columns will be used to determine how much extra
storage got purchased and how long it is valid. It is therefore
part of the total namespace storage limit.

We are not adding those two columns to the namespace table
directly because we want to reduce the amount of columns there.

changelogs/unreleased/nicolasdular-additional-purchased-storage-db.yml

+---
+title: Create namespace_limits table with additional purchase columns
+merge_request: 34746
+author:
+type: added

db/migrate/20200617150041_create_namespace_limits.rb

+# frozen_string_literal: true
+
+class CreateNamespaceLimits < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    with_lock_retries do
+      create_table :namespace_limits, id: false do |t|
+        t.bigint :additional_purchased_storage_size, default: 0, null: false
+        t.date :additional_purchased_storage_ends_on, null: true
+
+        t.references :namespace, primary_key: true, default: nil, type: :integer, index: false, foreign_key: { on_delete: :cascade }
+      end
+    end
+  end
+
+  def down
+    drop_table :namespace_limits # rubocop:disable Migration/DropTable
+  end
+end

db/structure.sql

@@ -4258,6 +4258,12 @@ CREATE TABLE public.namespace_aggregation_schedules (
     namespace_id integer NOT NULL
 );
 
+CREATE TABLE public.namespace_limits (
+    additional_purchased_storage_size bigint DEFAULT 0 NOT NULL,
+    additional_purchased_storage_ends_on date,
+    namespace_id integer NOT NULL
+);
+
 CREATE TABLE public.namespace_root_storage_statistics (
     namespace_id integer NOT NULL,
     updated_at timestamp with time zone NOT NULL,
@@ -8718,6 +8724,9 @@ ALTER TABLE ONLY public.milestones
 ALTER TABLE ONLY public.namespace_aggregation_schedules
     ADD CONSTRAINT namespace_aggregation_schedules_pkey PRIMARY KEY (namespace_id);
 
+ALTER TABLE ONLY public.namespace_limits
+    ADD CONSTRAINT namespace_limits_pkey PRIMARY KEY (namespace_id);
+
 ALTER TABLE ONLY public.namespace_root_storage_statistics
     ADD CONSTRAINT namespace_root_storage_statistics_pkey PRIMARY KEY (namespace_id);
 
@@ -12319,6 +12328,9 @@ ALTER TABLE ONLY public.resource_label_events
 ALTER TABLE ONLY public.approval_merge_request_rules_groups
     ADD CONSTRAINT fk_rails_5b2ecf6139 FOREIGN KEY (approval_merge_request_rule_id) REFERENCES public.approval_merge_request_rules(id) ON DELETE CASCADE;
 
+ALTER TABLE ONLY public.namespace_limits
+    ADD CONSTRAINT fk_rails_5b3f2bc334 FOREIGN KEY (namespace_id) REFERENCES public.namespaces(id) ON DELETE CASCADE;
+
 ALTER TABLE ONLY public.protected_environment_deploy_access_levels
     ADD CONSTRAINT fk_rails_5b9f6970fe FOREIGN KEY (user_id) REFERENCES public.users(id) ON DELETE CASCADE;
 
@@ -14088,6 +14100,7 @@ COPY "schema_migrations" (version) FROM STDIN;
 20200617001637
 20200617001848
 20200617002030
+20200617150041
 20200618105638
 20200618134223
 20200618134723