Update to allow a Book to have no Publisher.

priv/repo/migrations/20250603150057_update_to_allow_a_book_to_have_no_publisher.exs

@@ -0,0 +1,21 @@
+defmodule DecentralisedBookIndex.Repo.Migrations.UpdateToAllowABookToHaveNoPublisher do
+  @moduledoc """
+  Updates resources based on their most recent snapshots.
+
+  This file was autogenerated with `mix ash_postgres.generate_migrations`
+  """
+
+  use Ecto.Migration
+
+  def up do
+    alter table(:books) do
+      modify :publisher_id, :uuid, null: true
+    end
+  end
+
+  def down do
+    alter table(:books) do
+      modify :publisher_id, :uuid, null: false
+    end
+  end
+end