N+1 prevention with includes and preload

                  module Api
  module V1
    class PostsController < BaseController
      def index
        # Eager load author and recent comments with their authors
        posts = Post.published
                    .includes(:author, comments: [:author])
                    .order(created_at: :desc)
                    .page(params[:page])
                    .per(20)

        render json: posts, include: ['author', 'comments', 'comments.author']
      end

      def show
        # Eager load all associations needed for detail view
        post = Post.includes(:author, :tags, comments: [:author])
                   .find(params[:id])

        render json: post, include: ['author', 'tags', 'comments', 'comments.author']
      end
    end
  end
end