Move command classes to domain namespaces

They will probably be refactored away at a later stage (when we get
rid of the command bus). Until then, this lets us remove the
Flarum\Core namespace and actually feels quite clean.

src/Post/Command/PostReply.php

@@ -0,0 +1,59 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Post\Command;
+
+use Flarum\User\User;
+
+class PostReply
+{
+    /**
+     * The ID of the discussion to post the reply to.
+     *
+     * @var int
+     */
+    public $discussionId;
+
+    /**
+     * The user who is performing the action.
+     *
+     * @var User
+     */
+    public $actor;
+
+    /**
+     * The attributes to assign to the new post.
+     *
+     * @var array
+     */
+    public $data;
+
+    /**
+     * The IP address of the actor.
+     *
+     * @var string
+     */
+    public $ipAddress;
+
+    /**
+     * @param int $discussionId The ID of the discussion to post the reply to.
+     * @param User $actor The user who is performing the action.
+     * @param array $data The attributes to assign to the new post.
+     * @param string $ipAddress The IP address of the actor.
+     */
+    public function __construct($discussionId, User $actor, array $data, $ipAddress = null)
+    {
+        $this->discussionId = $discussionId;
+        $this->actor = $actor;
+        $this->data = $data;
+        $this->ipAddress = $ipAddress;
+    }
+}