docs: Add new plan for backend structure

backend/src/app.module.ts

@@ -6,6 +6,8 @@ import { UsersModule } from './users/users.module';
 import { AuthModule } from './auth/auth.module';
 import { ServeStaticModule } from '@nestjs/serve-static';
 import { join } from 'path';
+import { MediaModule } from './media/media.module';
+import { SourcesModule } from './sources/sources.module';
 
 @Module({
   imports: [
@@ -15,6 +17,8 @@ import { join } from 'path';
     ServeStaticModule.forRoot({
       rootPath: join(__dirname, '../dist'),
     }),
+    MediaModule,
+    SourcesModule,
   ],
   controllers: [AppController],
   providers: [AppService],