gistfile1.txt

def render("product.json", %{product: product}) do
  %{id: product.id,
    name: product.name,
    description: product.description,
    price: product.price}
  |> add_options(product)
end

defp add_options(json, %{product: product}) do
  options =
    product
    |> ExRushlookApi.Repo.preload(:options)
    |> render_many(ExRushlookApi.OptionView, "show.json")
  Map.put(json, :options, options)
end

defp add_options(json, _product) do
  json
end