persist document to database after 2 seconds of no updates, initialize with current state when joining genserver

priv/repo/migrations/20231125011258_remove_state_and_add_contents_to_document.exs

@@ -0,0 +1,10 @@
+defmodule Poex.Repo.Migrations.RemoveStateAndAddContentsToDocument do
+  use Ecto.Migration
+
+  def change do
+    alter table(:pad_documents) do
+      remove :state
+      add :contents, {:array, :map}, default: []
+    end
+  end
+end