LaravelEloquent：致命错误：在非对象上调用成员函数 connection()

我正在Laravel 4中构建一个包，但在try 访问数据库时出现了一个非对象错误，该数据库似乎是一个正确实例化的对象.以下是设置:

正在讨论的配置和类:

composer.json:

...
"autoload": {
        "classmap": [
            "app/commands",
            "app/controllers",
            "app/models",
            "app/database/migrations",
            "app/database/seeds",
            "app/tests/TestCase.php"
        ],
        "psr-0": {
            "Vendor\\Chat": "src/vendor/chat/src"
        }  
    }
...

The class:

namespace Vendor\Chat;

use Illuminate\Database\Eloquent\Model as Eloquent;


class ChatHistory extends Eloquent
{
    protected $table = 'chat_history';

    protected $fillable = array('message', 'user_id', 'room_token');

    public function __construct($attributes = array())
    {
        parent::__construct($attributes);
    }

}

The call:

$message = new Message($msg);

$history = new ChatHistory;
$history->create(array(
                 'room_token' => $message->getRoomToken(),
                 'user_id' => $message->getUserId(),
                 'message' => $message->getMessage(),
              ));

The error:

PHP Fatal error:  Call to a member function connection() on a non-object in /home/vagrant/project/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php on line 2894

我相信我错过了一些基本的东西.谢谢你的帮助！

编辑:

下面是实例化ChatHistory并调用write的类:

namespace Vendor\Chat;

use Ratchet\MessageComponentInterface;
use Ratchet\ConnectionInterface;

use Vendor\Chat\Client;
use Vendor\Chat\Message;
use Vendor\Chat\ChatHistory;

use Illuminate\Database\Model;

class Chat implements MessageComponentInterface {

    protected $app;

    protected $clients;

    public function __construct() 
    {
        $this->clients = new \SplObjectStorage;
    }

    public function onOpen(ConnectionInterface $conn) 
    {
        $client = new Client;
        $client->setId($conn->resourceId);
        $client->setSocket($conn);

        $this->clients->attach($client);
    }

    public function onMessage(ConnectionInterface $conn, $msg) 
    {
        $message = new Message($msg);

        $history = new ChatHistory;
        ChatHistory::create(array(
                     'room_token' => $message->getRoomToken(),
                     'user_id' => $message->getUserId(),
                     'message' => $message->getMessage(),
                  ));
        /* error here */
        /* ... */ 
    }

    public function onClose(ConnectionInterface $conn) 
    {
        $this->clients->detach($conn);
    }

    public function onError(ConnectionInterface $conn, \Exception $e) 
    {
        $conn->close();
    }

    protected function getClientByConn(ConnectionInterface $conn)
    {
        foreach($this->clients as $client) {
            if($client->getSocket() === $conn) {
                return $client;
            } 
        } 

        return null;
    }
}

DB不可用的事实表明Eloquent没有被加载到顶层？