Bazaar-backend: Add user entity field to members table

A new field has been added to the members table. When a user has
requested to be added to a project the "identityApi" is used to get the
entity ref of the user.

Signed-off-by: Niklas Aronsson <niklasar@axis.com>

plugins/bazaar-backend/migrations/20220817150443_add_member_entity_ref.js

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2022 The Backstage Authors
+ *
+ * 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.
+ */
+
+exports.up = async function up(knex) {
+  await knex.schema.alterTable('members', table => {
+    table.string('user_ref').nullable();
+  });
+};
+
+exports.down = async function down(knex) {
+  return knex.schema.table('members', table => {
+    table.dropColumn('user_ref');
+  });
+};