Add PostgreSQL Support (#3)

Reviewed-on: #3

tests/unit/Mapper/StringMapperTest.php

@@ -3,8 +3,13 @@
 namespace Test\Unit\Mapper;
 
 use BitBadger\PDODocument\Mapper\StringMapper;
+use PHPUnit\Framework\Attributes\TestDox;
 use PHPUnit\Framework\TestCase;
 
+/**
+ * Unit tests for the StringMapper class
+ */
+#[TestDox('String Mapper (Unit tests)')]
 class StringMapperTest extends TestCase
 {
     public function testMapSucceedsWhenFieldIsPresentAndString()