diff --git a/src/Repository/NameserverRepository.php b/src/Repository/NameserverRepository.php
index 75d2d65..dc4e6f1 100644
--- a/src/Repository/NameserverRepository.php
+++ b/src/Repository/NameserverRepository.php
@@ -12,7 +12,7 @@ use PDOException;
  */
 class NameserverRepository
 {
-	public function __construct(private DatabaseConnection $databaseConnection)
+	public function __construct(private readonly DatabaseConnection $databaseConnection)
 	{
 	}