chore: commit remaining integration files, PM2 single instance, PRD doc

apps/server/src/integration/integration.module.ts

@@ -0,0 +1,12 @@
+import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { Department, User } from '../entities';
+import { DingTalkService } from './dingtalk.service';
+import { WeComService } from './wecom.service';
+
+@Module({
+  imports: [TypeOrmModule.forFeature([Department, User])],
+  providers: [DingTalkService, WeComService],
+  exports: [DingTalkService, WeComService],
+})
+export class IntegrationModule {}