Refs mongo dont working nestjs with graphql - mongodb

Question

I believe I am missing something I already tried to add populate but it doesn't work either I don't know what it is and I can't find any examples about relationships
I want to select many items for one user.
In items it references user but in user items[] returns blank and array is empty in mongo
Users Module
imports: [MongooseModule.forFeature([{ name: 'User', schema: UserSchema }])],
UserSchema
export const UsersSchema = new mongoose.Schema({
[...]
items: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Items'}],
});
Items module
imports: [
MongooseModule.forFeature([{ name: 'Item', schema: ItemSchema }]),
],
ItemSchema
export const ItemSchema = new mongoose.Schema({
title: String,
price: Number,
description: String,
user: { type: mongoose.Schema.Types.ObjectId, ref: 'Users'},
});
Mutation to create item in items.resolver.ts
#Mutation(() => ItemType)
async createItem(#Args('input') input: ItemInput): Promise<ItemInput> {
return this.itemsService.create(input);
}
and service with create method
async create(createItemDto: ItemInput): Promise<ItemType> {
const createdItem = new this.itemModel(createItemDto);
return await createdItem.save();
}
Item reference in users only shows an empty array in mongo, but my user reference in items shows object id as below