Grails 3 & relational domain mapping with Mongo - mongodb

Question

Trying to figure out if there is a way that I can relate these two domain objects in a similar way that I would if I were connected to an Oracle db.
gradle.properties
grailsVersion=3.2.9
gradleWrapperVersion=2.9
gormVersion=6.1.3.RELEASE
build.gradle
compile "org.grails.plugins:mongodb:6.1.3"
compile "org.mongodb:mongodb-driver:3.4.2"
Domain objects:
class Store {
Long id
// other properties
Long sellerId
}
class Seller {
Long id
// other properties
}
I thought to do something like this:
class Store {
Long id
// other properties
Long sellerId
Seller seller
Seller getSeller {
Seller.findById(this.sellerId)
}
}
In the case above, only sellerId is persisted to Mongo since it is not marked as embedded. This works great if I reference it in grails code - giving me valid values for all of the properties in store.seller. However, if I return a store from a controller, store.seller does not come through fully. The response JSON for store looks like this (notice how seller ONLY has the id property):
{
id: 1,
// other properties
seller: {
id: 22
}
}
I have also tried something like this but afterLoad never gets hit:
class Store {
Long id
// other properties
Long sellerId
Seller seller
def afterLoad() {
seller = Seller.findById(this.sellerId)
}
}
Is there a better way to go about doing this?