changed docker file nest to avoid rebuild everything each time, and small changes in chat gateway

tests_hugo/nest_course/src/app.module.ts

@@ -0,0 +1,12 @@
+import { Module } from '@nestjs/common';
+import { AppController } from './app.controller';
+import { AppService } from './app.service';
+import { CoffeesController } from './coffees/coffees.controller';
+import { CoffeesService } from './coffees/coffees.service';
+
+@Module({
+  imports: [],
+  controllers: [AppController, CoffeesController],
+  providers: [AppService, CoffeesService],
+})
+export class AppModule {}