Add demo mode

backend/src/managers/demo/demomanager.module.ts

@@ -0,0 +1,20 @@
+import { Module, OnModuleInit } from '@nestjs/common';
+import { ImageDBModule } from '../../collections/imagedb/imagedb.module';
+import Config from '../../env';
+import { DemoManagerService } from './demomanager.service';
+
+@Module({
+  imports: [ImageDBModule],
+  providers: [DemoManagerService],
+})
+export class DemoManagerModule implements OnModuleInit {
+  constructor(private readonly demoManagerService: DemoManagerService) {}
+
+  private interval: NodeJS.Timeout;
+
+  onModuleInit() {
+    if (Config.demo.enabled) {
+      setInterval(this.demoManagerService.execute, Config.demo.interval);
+    }
+  }
+}