Register Sortable Fixtures to autoloader

tests/bootstrap.php

@@ -44,6 +44,7 @@ $loader->registerNamespaces(array(
     'Timestampable\\Fixture'     => __DIR__.'/Gedmo',
     'Tree\\Fixture'              => __DIR__.'/Gedmo',
     'Sluggable\\Fixture'         => __DIR__.'/Gedmo',
+    'Sortable\\Fixture'          => __DIR__.'/Gedmo',
     'Mapping\\Fixture'           => __DIR__.'/Gedmo',
     'Loggable\\Fixture'          => __DIR__.'/Gedmo',
     'Wrapper\\Fixture'           => __DIR__.'/Gedmo',