Rails 7.1: implementing ActiveModel Serializer not including nested attributes correctly
I'm working with an scenario where my ActiveModel Serializers are not including nested attributes as expected in my Rails 7.1 application. I have a `User` model that has many `Posts`, and I want to include the associated posts when serializing a user instance. However, the serialized output only shows the user attributes without the nested posts. Here's my current setup: ```ruby class User < ApplicationRecord has_many :posts end class Post < ApplicationRecord belongs_to :user end ``` I created a serializer for the `User` model: ```ruby class UserSerializer < ActiveModel::Serializer attributes :id, :name, :email has_many :posts end ``` And a corresponding serializer for the `Post` model: ```ruby class PostSerializer < ActiveModel::Serializer attributes :id, :title, :content end ``` When I try to serialize a user instance like this: ```ruby user = User.includes(:posts).find(1) render json: user ``` I expect to see a JSON response that includes the user's posts, but I only get: ```json { "id": 1, "name": "John Doe", "email": "john.doe@example.com" } ``` I have checked that the user actually has posts associated with it, so I suspect it might be an scenario with how the serializers are set up or how I'm using the `includes` method. I also tried adding `include: :posts` to the `render` method: ```ruby render json: user, include: ['posts'] ``` But this still doesn't work. Can someone explain why the nested attributes are not being included, or if there's a specific way to make it work in this version of Rails? Any pointers in the right direction?