Add HerdWasRenamed event to the model

spec/Elewant/Herding/Model/Events/HerdWasRenamedSpec.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace spec\Elewant\Herding\Model\Events;
+
+use Elewant\Herding\Model\Events\HerdWasRenamed;
+use Elewant\Herding\Model\HerdId;
+use PhpSpec\ObjectBehavior;
+
+class HerdWasRenamedSpec extends ObjectBehavior
+{
+    function it_took_place()
+    {
+        $herdId = HerdId::fromString('00000000-0000-0000-0000-000000000000');
+
+        $this->beConstructedThrough(
+            'tookPlace',
+            [
+                $herdId,
+                'new herd name',
+            ]
+        );
+
+        $this->shouldHaveType(HerdWasRenamed::class);
+        $this->aggregateId()->shouldReturn($herdId->toString());
+        $this->herdId()->shouldEqual($herdId);
+        $this->newHerdName()->shouldEqual('new herd name');
+    }
+}

src/Elewant/Herding/Model/Events/HerdWasRenamed.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Elewant\Herding\Model\Events;
+
+use Elewant\Herding\Model\HerdId;
+use Prooph\EventSourcing\AggregateChanged;
+
+class HerdWasRenamed extends AggregateChanged
+{
+    public static function tookPlace(HerdId $herdId, string $newHerdName): self
+    {
+        return self::occur(
+            $herdId->toString(),
+            [
+                'newHerdName' => $newHerdName,
+            ]
+        );
+    }
+
+    public function herdId(): HerdId
+    {
+        return HerdId::fromString($this->aggregateId());
+    }
+
+    public function newHerdName(): string
+    {
+        return $this->payload['newHerdName'];
+    }
+
+}