Start adding SQLite database access

src/Endpoint.php

@@ -0,0 +1,9 @@
+<?php declare(strict_types=1);
+
+namespace Lewisdale\Webmentions;
+
+use Lewisdale\Webmentions\Gateways\WebmentionGatewayInterface;
+
+class Endpoint {
+    private readonly WebmentionGatewayInterface $gateway;
+}