Support preloading associations in embedded schemas - #3368

defmodule User do
  schema "users" do
    field :name, :string
  end
end

defmodule Post do
  schema "posts" do
    embeds_many :comments, Comment
  end
end

defmodule Comment do
  embedded_schema "posts" do
    field :message, :string
    belongs_to :author, User
  end
end

# If I have a `Comment` struct, I'd like to be able to preload its `author
comment = Repo.get(Comment, comment_id) |> Repo.preload(:author)