Allow updating incidents when the incident has no associated user

app/Models/Incident.php

@@ -120,7 +120,7 @@ class Incident extends Model implements HasPresenter
      * @var string[]
      */
     public $rules = [
-        'user_id'       => 'required|int',
+        'user_id'       => 'nullable|int',
         'component_id'  => 'nullable|int',
         'name'          => 'required|string',
         'status'        => 'required|int',

tests/Api/IncidentTest.php

@@ -179,6 +179,23 @@ class IncidentTest extends AbstractApiTestCase
         ]);
     }
 
+    public function test_can_update_incident_when_no_user_is_associated()
+    {
+        $incident = factory(Incident::class)->create(['user_id' => null]);
+        $this->beUser();
+        $this->expectsEvents(IncidentWasUpdatedEvent::class);
+
+        $response = $this->json('PUT', '/api/v1/incidents/1', [
+            'name'     => 'Updated incident name',
+        ]);
+
+        $response->assertStatus(200);
+        $response->assertJsonFragment([
+            'name'    => 'Updated incident name',
+            'user_id' => null,
+        ]);
+    }
+
     public function test_can_delete_incident()
     {
         $this->beUser();