diff --git a/extensions/tags/src/CategoriesHandler.php b/extensions/tags/src/CategoriesHandler.php
deleted file mode 100755
index c21b49753..000000000
--- a/extensions/tags/src/CategoriesHandler.php
+++ /dev/null
@@ -1,66 +0,0 @@
-<?php namespace Flarum\Categories;
-
-use Flarum\Categories\Events\DiscussionWasMoved;
-use Flarum\Core\Events\ModelCall;
-use Flarum\Core\Events\RegisterDiscussionGambits;
-use Flarum\Core\Events\DiscussionWillBeSaved;
-use Flarum\Core\Models\Discussion;
-use Flarum\Api\Events\SerializeRelationship;
-use Flarum\Api\Serializers\DiscussionSerializer;
-use Flarum\Forum\Events\RenderView;
-
-class CategoriesHandler
-{
-    public function subscribe($events)
-    {
-        $events->listen('Flarum\Forum\Events\RenderView', __CLASS__.'@renderForum');
-        $events->listen('Flarum\Api\Events\SerializeRelationship', __CLASS__.'@serializeRelationship');
-        $events->listen('Flarum\Core\Events\RegisterDiscussionGambits', __CLASS__.'@registerDiscussionGambits');
-        $events->listen('Flarum\Core\Events\DiscussionWillBeSaved', __CLASS__.'@whenDiscussionWillBeSaved');
-    }
-
-    public function renderForum(RenderView $event)
-    {
-        $root = __DIR__.'/..';
-
-        $event->assets->addFile([
-            $root.'/js/dist/extension.js',
-            $root.'/less/categories.less'
-        ]);
-
-        $serializer = new CategorySerializer($event->action->actor);
-        $event->view->data = array_merge($event->view->data, $serializer->collection(Category::orderBy('position')->get())->toArray());
-    }
-
-    public function whenDiscussionWillBeSaved(DiscussionWillBeSaved $event)
-    {
-        if (isset($event->command->data['links']['category']['linkage'])) {
-            $linkage = $event->command->data['links']['category']['linkage'];
-
-            $categoryId = (int) $linkage['id'];
-            $discussion = $event->discussion;
-            $user = $event->command->user;
-
-            $oldCategoryId = (int) $discussion->category_id;
-
-            if ($oldCategoryId === $categoryId) {
-                return;
-            }
-
-            $discussion->category_id = $categoryId;
-            $discussion->raise(new DiscussionWasMoved($discussion, $user, $oldCategoryId));
-        }
-    }
-
-    public function registerDiscussionGambits(RegisterDiscussionGambits $event)
-    {
-        $event->gambits->add('Flarum\Categories\CategoryGambit');
-    }
-
-    public function serializeRelationship(SerializeRelationship $event)
-    {
-        if ($event->serializer instanceof DiscussionSerializer && $event->name === 'category') {
-            return $event->serializer->hasOne('Flarum\Categories\CategorySerializer', 'category');
-        }
-    }
-}
diff --git a/extensions/tags/src/CategoriesServiceProvider.php b/extensions/tags/src/CategoriesServiceProvider.php
index 6ce82ce4a..79804e807 100644
--- a/extensions/tags/src/CategoriesServiceProvider.php
+++ b/extensions/tags/src/CategoriesServiceProvider.php
@@ -1,12 +1,9 @@
 <?php namespace Flarum\Categories;
 
-use Illuminate\Support\ServiceProvider;
-use Illuminate\Contracts\Events\Dispatcher;
-use Flarum\Core\Models\Post;
-use Flarum\Core\Models\Discussion;
-use Flarum\Core\Notifications\Notifier;
+use Flarum\Support\ServiceProvider;
 use Flarum\Api\Actions\Discussions\IndexAction as DiscussionsIndexAction;
 use Flarum\Api\Actions\Discussions\ShowAction as DiscussionsShowAction;
+use Illuminate\Contracts\Events\Dispatcher;
 
 class CategoriesServiceProvider extends ServiceProvider
 {
@@ -15,26 +12,36 @@ class CategoriesServiceProvider extends ServiceProvider
      *
      * @return void
      */
-    public function boot(Dispatcher $events, Notifier $notifier)
+    public function boot(Dispatcher $events)
     {
-        $events->subscribe('Flarum\Categories\CategoriesHandler');
-        $events->subscribe('Flarum\Categories\DiscussionMovedNotifier');
+        $events->subscribe('Flarum\Categories\Handlers\DiscussionMovedNotifier');
+        $events->subscribe('Flarum\Categories\Handlers\CategoryPreloader');
+        $events->subscribe('Flarum\Categories\Handlers\CategorySaver');
+
+        $this->forumAssets([
+            __DIR__.'/../js/dist/extension.js',
+            __DIR__.'/../less/categories.less'
+        ]);
+
+        $this->postType('Flarum\Categories\DiscussionMovedPost');
+
+        $this->discussionGambit('Flarum\Categories\CategoryGambit');
+
+        $this->notificationType('Flarum\Categories\DiscussionMovedNotification', ['alert' => true]);
+
+        $this->relationship('Flarum\Core\Models\Discussion', 'belongsTo', 'category', 'Flarum\Categories\Category');
+
+        $this->serializeRelationship('Flarum\Api\Serializers\DiscussionSerializer', 'hasOne', 'category', 'Flarum\Categories\CategorySerializer');
 
-        // Add the category relationship to the Discussion model, and include
-        // it in discussion-related API actions by default.
-        Discussion::addRelationship('category', function ($model) {
-            return $model->belongsTo('Flarum\Categories\Category', null, null, 'category');
-        });
         DiscussionsIndexAction::$include['category'] = true;
         DiscussionsShowAction::$include['category'] = true;
-
-        // Add a new post and notification type to represent a discussion
-        // being moved from one category to another.
-        Post::addType('Flarum\Categories\DiscussionMovedPost');
-
-        $notifier->registerType('Flarum\Categories\DiscussionMovedNotification', ['alert' => true]);
     }
 
+    /**
+     * Register the service provider.
+     *
+     * @return void
+     */
     public function register()
     {
         $this->app->bind(
diff --git a/extensions/tags/src/Handlers/CategoryPreloader.php b/extensions/tags/src/Handlers/CategoryPreloader.php
new file mode 100755
index 000000000..a6ac6e9f8
--- /dev/null
+++ b/extensions/tags/src/Handlers/CategoryPreloader.php
@@ -0,0 +1,19 @@
+<?php namespace Flarum\Categories\Handlers;
+
+use Flarum\Categories\Category;
+use Flarum\Categories\CategorySerializer;
+use Flarum\Forum\Events\RenderView;
+
+class CategoryPreloader
+{
+    public function subscribe($events)
+    {
+        $events->listen('Flarum\Forum\Events\RenderView', __CLASS__.'@renderForum');
+    }
+
+    public function renderForum(RenderView $event)
+    {
+        $serializer = new CategorySerializer($event->action->actor);
+        $event->view->data = array_merge($event->view->data, $serializer->collection(Category::orderBy('position')->get())->toArray());
+    }
+}
diff --git a/extensions/tags/src/Handlers/CategorySaver.php b/extensions/tags/src/Handlers/CategorySaver.php
new file mode 100755
index 000000000..33870cdc1
--- /dev/null
+++ b/extensions/tags/src/Handlers/CategorySaver.php
@@ -0,0 +1,32 @@
+<?php namespace Flarum\Categories\Handlers;
+
+use Flarum\Categories\Events\DiscussionWasMoved;
+use Flarum\Core\Events\DiscussionWillBeSaved;
+
+class CategorySaver
+{
+    public function subscribe($events)
+    {
+        $events->listen('Flarum\Core\Events\DiscussionWillBeSaved', __CLASS__.'@whenDiscussionWillBeSaved');
+    }
+
+    public function whenDiscussionWillBeSaved(DiscussionWillBeSaved $event)
+    {
+        if (isset($event->command->data['links']['category']['linkage'])) {
+            $linkage = $event->command->data['links']['category']['linkage'];
+
+            $categoryId = (int) $linkage['id'];
+            $discussion = $event->discussion;
+            $user = $event->command->user;
+
+            $oldCategoryId = (int) $discussion->category_id;
+
+            if ($oldCategoryId === $categoryId) {
+                return;
+            }
+
+            $discussion->category_id = $categoryId;
+            $discussion->raise(new DiscussionWasMoved($discussion, $user, $oldCategoryId));
+        }
+    }
+}
diff --git a/extensions/tags/src/DiscussionMovedNotifier.php b/extensions/tags/src/Handlers/DiscussionMovedNotifier.php
similarity index 91%
rename from extensions/tags/src/DiscussionMovedNotifier.php
rename to extensions/tags/src/Handlers/DiscussionMovedNotifier.php
index 71adacb55..c50ba89fa 100755
--- a/extensions/tags/src/DiscussionMovedNotifier.php
+++ b/extensions/tags/src/Handlers/DiscussionMovedNotifier.php
@@ -1,5 +1,7 @@
-<?php namespace Flarum\Categories;
+<?php namespace Flarum\Categories\Handlers;
 
+use Flarum\Categories\DiscussionMovedPost;
+use Flarum\Categories\DiscussionMovedNotification;
 use Flarum\Categories\Events\DiscussionWasMoved;
 use Flarum\Core\Notifications\Notifier;
 use Illuminate\Contracts\Events\Dispatcher;