Add migration with new index for short_url_id+potential_bot on visits table

data/migrations/Version20230211171904.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ShlinkMigrations;
+
+use Doctrine\DBAL\Platforms\MySQLPlatform;
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20230211171904 extends AbstractMigration
+{
+    private const INDEX_NAME = 'IDX_visits_potential_bot';
+
+    public function up(Schema $schema): void
+    {
+        $visits = $schema->getTable('visits');
+        $this->skipIf($visits->hasIndex(self::INDEX_NAME));
+
+        $visits->addIndex(['short_url_id', 'potential_bot'], self::INDEX_NAME);
+    }
+
+    public function isTransactional(): bool
+    {
+        return ! ($this->connection->getDatabasePlatform() instanceof MySQLPlatform);
+    }
+}