Use new extenders (#22)

extensions/sticky/extend.php

@@ -7,8 +7,11 @@
  * LICENSE file that was distributed with this source code.
  */
 
+use Flarum\Api\Controller\ListDiscussionsController;
+use Flarum\Api\Serializer\DiscussionSerializer;
 use Flarum\Extend;
 use Flarum\Sticky\Listener;
+use Flarum\Sticky\Post\DiscussionStickiedPost;
 use Illuminate\Contracts\Events\Dispatcher;
 
 return [
@@ -16,13 +19,26 @@ return [
         ->js(__DIR__.'/js/dist/forum.js')
         ->css(__DIR__.'/less/forum.less'),
 
+    (new Extend\Post())
+        ->type(DiscussionStickiedPost::class),
+
+    (new Extend\ApiSerializer(DiscussionSerializer::class))
+        ->attribute('isSticky', function (DiscussionSerializer $serializer, $discussion) {
+            return (bool) $discussion->is_sticky;
+        })
+        ->attribute('canSticky', function (DiscussionSerializer $serializer, $discussion) {
+            return (bool) $serializer->getActor()->can('sticky', $discussion);
+        }),
+
+    (new Extend\ApiController(ListDiscussionsController::class))
+        ->addInclude('firstPost'),
+
     (new Extend\Frontend('admin'))
         ->js(__DIR__.'/js/dist/admin.js'),
 
     new Extend\Locales(__DIR__.'/locale'),
 
     function (Dispatcher $events) {
-        $events->subscribe(Listener\AddApiAttributes::class);
         $events->subscribe(Listener\CreatePostWhenDiscussionIsStickied::class);
         $events->subscribe(Listener\PinStickiedDiscussionsToTop::class);
         $events->subscribe(Listener\SaveStickyToDatabase::class);