Nest can’t resolve dependencies of the ItemsService (?). Please make sure that the argument at index [0] is available in the AppModule context

In order to solve it you have to remove the ItemsController and ItemsService imports from the app.module.ts file.

This was the solution because:

You already import ItemsController and ItemsService in your items.module.ts file so it’s not necessary to import
them again in the app.module.ts file.
In your items.module.ts you have the next line:
```
@Module({
  imports: [MongooseModule.forFeature([{ name: 'Item', schema: ItemSchema }])],
  ...
})
```
which is necessary to make the dependency injection in the items.service.ts file works, as you can check in the
app.module.ts file you don’t have that line.
Of course you can add that line to your app.module.ts file but then there’s no sense to create the
items.module.ts file.

Check my repo xD.