feat: add initial database migration

Signed-off-by: David Mehren <git@herrmehren.de>

backend/src/ormconfig.ts

@@ -0,0 +1,28 @@
+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import { NestFactory } from '@nestjs/core';
+import { NestExpressApplication } from '@nestjs/platform-express';
+import { DataSource } from 'typeorm';
+
+import { AppModule } from './app.module';
+import { AppConfig } from './config/app.config';
+import { Loglevel } from './config/loglevel.enum';
+import { ConsoleLoggerService } from './logger/console-logger.service';
+
+async function buildDataSource(): Promise<DataSource> {
+  // We create a new app instance to let it discover entities
+  const app = await NestFactory.create<NestExpressApplication>(AppModule, {
+    logger: new ConsoleLoggerService({ loglevel: Loglevel.TRACE } as AppConfig),
+  });
+  const dataSource = app.get(DataSource);
+
+  // The migration CLI does not want an existing connection
+  await dataSource.destroy();
+
+  return dataSource;
+}
+
+export default buildDataSource();