Represents nested fixtures that are synced after the parent.

The parent's ID is injected into each nested record via the foreign_key.

With a fixture module

defmodule MyApp.Seeds.Product do
  use Sow, schema: MyApp.Product, keys: [:slug]

  def records do
    %{
      slug: "premium",
      variants: Sow.has_many(MyApp.Seeds.ProductVariant, foreign_key: :product_id)
    }
  end
end

With inline records

def records do
  %{
    slug: "premium",
    variants: Sow.has_many_inline(
      [
        %{sku: "SMALL", name: "Small"},
        %{sku: "LARGE", name: "Large"}
      ],
      schema: MyApp.ProductVariant,
      foreign_key: :product_id,
      keys: [:product_id, :sku]
    )
  }
end

During sync:

1. Parent record is inserted/updated first
2. Each nested record gets product_id: parent.id injected
3. Nested records are then synced