未定义的索引：Laravel 5部署的驱动程序

Question

我用这个简短的shell脚本（gist link）创建了一个全新的Laravel 5项目，并在Fortrabbit上创建了一个应用程序来部署它。当我把所有东西都检查成git并将其推高时我得到了以下错误：

Deployment file:
  not found

Pre-script:
  not found
  0ms

Composer:
  - - -
  Loading composer repositories with package information
  Installing dependencies (including require-dev) from lock file
  Nothing to install or update
  Generating optimized autoload files
  > Illuminate\Foundation\ComposerScripts::postInstall
  > php artisan optimize



    [ErrorException]         
    Undefined index: driver  



  Script php artisan optimize handling the post-install-cmd event returned with error code 1

  - - -


A B O R T E D

  !! Failure in build execution: Failure in composer execution

我的composer.json是Laravel安装的默认设置：

"scripts": {
    "post-root-package-install": [
        "php -r \"file_exists('.env') || copy('.env.example', '.env');\""
    ],
    "post-create-project-cmd": [
        "php artisan key:generate"
    ],
    "post-install-cmd": [
        "Illuminate\\Foundation\\ComposerScripts::postInstall",
        "php artisan optimize"
    ],
    "post-update-cmd": [
        "Illuminate\\Foundation\\ComposerScripts::postUpdate",
        "php artisan optimize"
    ]
},

导致此错误的原因是什么？如何解决？谢谢