Added new columns for extra tracking in visits table

data/migrations/Version20210207100807.php

@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ShlinkMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\DBAL\Types\Types;
+use Doctrine\Migrations\AbstractMigration;
+use Shlinkio\Shlink\Core\Entity\Visit;
+use Shlinkio\Shlink\Core\Model\Visitor;
+
+final class Version20210207100807 extends AbstractMigration
+{
+    public function up(Schema $schema): void
+    {
+        $visits = $schema->getTable('visits');
+        $shortUrlId = $visits->getColumn('short_url_id');
+
+        $this->skipIf(! $shortUrlId->getNotnull());
+
+        $shortUrlId->setNotnull(false);
+
+        $visits->addColumn('visited_url', Types::STRING, [
+            'length' => Visitor::VISITED_URL_MAX_LENGTH,
+            'notnull' => false,
+        ]);
+        $visits->addColumn('type', Types::STRING, [
+            'length' => 255,
+            'default' => Visit::TYPE_VALID_SHORT_URL,
+        ]);
+    }
+
+    public function down(Schema $schema): void
+    {
+        $visits = $schema->getTable('visits');
+        $shortUrlId = $visits->getColumn('short_url_id');
+
+        $this->skipIf($shortUrlId->getNotnull());
+
+        $shortUrlId->setNotnull(true);
+        $visits->dropColumn('visited_url');
+        $visits->dropColumn('type');
+    }
+
+    /**
+     * @fixme Workaround for https://github.com/doctrine/migrations/issues/1104
+     */
+    public function isTransactional(): bool
+    {
+        return false;
+    }
+}