Add models and migrations

priv/repo/migrations/20250606100445_create_bookmarks.exs

@@ -0,0 +1,14 @@
+defmodule Nulla.Repo.Migrations.CreateBookmarks do
+  use Ecto.Migration
+
+  def change do
+    create table(:bookmarks) do
+      add :url, :string
+      add :user_id, references(:users, on_delete: :delete_all)
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create index(:bookmarks, [:user_id])
+  end
+end