Add `latest_pipeline_id` column to `vulnerability_statistics` table

Changelog: added

db/migrate/20210525184900_add_latest_pipeline_id_into_vulnerability_statistics_table.rb

+# frozen_string_literal: true
+
+class AddLatestPipelineIdIntoVulnerabilityStatisticsTable < ActiveRecord::Migration[6.0]
+  def change
+    add_column :vulnerability_statistics, :latest_pipeline_id, :bigint
+  end
+end

db/migrate/20210526181820_add_index_to_vulnerability_statistics_on_latest_pipeline_id.rb

+# frozen_string_literal: true
+
+class AddIndexToVulnerabilityStatisticsOnLatestPipelineId < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  INDEX_NAME = 'index_vulnerability_statistics_on_latest_pipeline_id'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :vulnerability_statistics, :latest_pipeline_id, name: INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index_by_name :vulnerability_statistics, INDEX_NAME
+  end
+end

db/migrate/20210526181821_add_foreign_key_for_latest_pipeline_id_to_ci_pipelines.rb

+# frozen_string_literal: true
+
+class AddForeignKeyForLatestPipelineIdToCiPipelines < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_foreign_key :vulnerability_statistics, :ci_pipelines, column: :latest_pipeline_id, on_delete: :nullify
+  end
+
+  def down
+    with_lock_retries do
+      remove_foreign_key_if_exists :vulnerability_statistics, :ci_pipelines
+    end
+  end
+end

db/schema_migrations/20210525184900

+ae91ea7481ea21ce29b4c0697f77fd83017c36d913739ed67e5c907a48c56f69
\ No newline at end of file

db/schema_migrations/20210526181820

+e72471e63dc108939473232437eda4c718382630c1173ae20023002d382e5ffa
\ No newline at end of file

db/schema_migrations/20210526181821

+3c53d85bec154ec68a23841d37317d10fa6c7c846bc5f54f5b7876081105ac7b
\ No newline at end of file

db/structure.sql

@@ -19247,7 +19247,8 @@ CREATE TABLE vulnerability_statistics (
     low integer DEFAULT 0 NOT NULL,
     unknown integer DEFAULT 0 NOT NULL,
     info integer DEFAULT 0 NOT NULL,
-    letter_grade smallint NOT NULL
+    letter_grade smallint NOT NULL,
+    latest_pipeline_id bigint
 );
 
 CREATE SEQUENCE vulnerability_statistics_id_seq
@@ -24863,6 +24864,8 @@ CREATE UNIQUE INDEX index_vulnerability_remediations_on_project_id_and_checksum
 
 CREATE UNIQUE INDEX index_vulnerability_scanners_on_project_id_and_external_id ON vulnerability_scanners USING btree (project_id, external_id);
 
+CREATE INDEX index_vulnerability_statistics_on_latest_pipeline_id ON vulnerability_statistics USING btree (latest_pipeline_id);
+
 CREATE INDEX index_vulnerability_statistics_on_letter_grade ON vulnerability_statistics USING btree (letter_grade);
 
 CREATE UNIQUE INDEX index_vulnerability_statistics_on_unique_project_id ON vulnerability_statistics USING btree (project_id);
@@ -25964,6 +25967,9 @@ ALTER TABLE ONLY sprints
 ALTER TABLE ONLY application_settings
     ADD CONSTRAINT fk_e8a145f3a7 FOREIGN KEY (instance_administrators_group_id) REFERENCES namespaces(id) ON DELETE SET NULL;
 
+ALTER TABLE ONLY vulnerability_statistics
+    ADD CONSTRAINT fk_e8b13c928f FOREIGN KEY (latest_pipeline_id) REFERENCES ci_pipelines(id) ON DELETE SET NULL;
+
 ALTER TABLE ONLY ci_triggers
     ADD CONSTRAINT fk_e8e10d1964 FOREIGN KEY (owner_id) REFERENCES users(id) ON DELETE CASCADE;