在Laravel 5.2中，我正在尝试与mongodb连接 . 我已按照https://github.com/jenssegers/laravel-mongodb中提到的步骤进行操作 . 在运行命令'php artisan migrate'时在迁移中创建表后，出现错误

[MongoConnectionException] Failed to connect to: localhost:27017: Authentication failed on database 'admin' with username 'admin': auth failed

迁移文件看起来像这样，只是用工匠创建它：

<?php

 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Database\Migrations\Migration;

class CreateUsersTable extends Migration
{
  /**
   * Run the migrations.
   *
   * @return void
  */
public function up()
{
    Schema::create('users', function (Blueprint $table) {
        $table->increments('id');
        $table->string("username")->unique();
        $table->string("password");
        $table->timestamps();
    });
}

 /**
  * Reverse the migrations.
  *
  * @return void
  */
  public function down()
   {
       Schema::drop('users');
   }
}

db config:

 'mongodb' => array(
        'driver'   => 'mongodb',
        'host'     => env('DB_HOST', 'localhost'),
        'port'     => env('DB_PORT', 27017),
        'database' => env('DB_DATABASE', '*****'),
        'username' => env('DB_USERNAME', 'admin'),
        'password' => env('DB_PASSWORD', 'admin'),
        'options' => array(
            'db' => env('DB_AUTH_DATABASE', '') // sets the authentication database required by mongo 3
        )
    ),

使用的版本：

"require": {
      "php": ">=5.5.9",
      "laravel/framework": "5.1.*",
      "jenssegers/mongodb": "^2.2"
   },

有人可以帮我解决这个问题

mongodb laravel-5 laravel-5.2