Fatal Error Laravel: Uncaught ReflectionException when i view my Site

I have the following error when i view my site.

My Error:

Fatal error: Uncaught ReflectionException: Class log does not exist in /home/vagrant/Code/in10km/vendor/laravel/framework/src/Illuminate/Container/Container.php:741> Stack trace: #0 /home/vagrant/Code/in10km/vendor/laravel/framework/src/Illuminate/Container/Container.php(741): ReflectionClass->__construct('log') #1 /home/vagrant/Code/in10km/vendor/laravel/framework/src/Illuminate/Container/Container.php(631): Illuminate\Container\Container->build('log', Array) #2 /home/vagrant/Code/in10km/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(674): Illuminate\Container\Container->make('log', Array) #3 /home/vagrant/Code/in10km/vendor/laravel/framework/src/Illuminate/Container/Container.php(842): Illuminate\Foundation\Application->make('log') #4 /home/vagrant/Code/in10km/vendor/laravel/framework/src/Illuminate/Container/Container.php(805): Illuminate\Container\Container->resolveClass(Object(ReflectionParameter)) > #5 /home/vagrant/Code/in10km/vendor/laravel/framework/src/Illuminate/Container/Container.php(774): Il in /home/vagrant/Code/in10km/vendor/laravel/framework/src/Illuminate/Container/Container.php on line 741

My Composer.json file is like this

{
    "name": "laravel/laravel",
    "description": "The Laravel Framework.",
    "keywords": ["framework", "laravel"],
    "license": "MIT",
    "type": "project",
    "require": {
        "php": ">=5.5.9",
        "laravel/framework": "5.1.*",
        "doctrine/dbal": "v2.4.2",
        "swiftmailer/swiftmailer": "^5.4",
        "guzzlehttp/guzzle": "~5.3|~6.0",       
        "chrisbjr/api-guard": "^2.3",
        "serverfireteam/panel": "1.3.*",
        "laravel/socialite": "^2.0"

    },
    "require-dev": {
        "fzaninotto/faker": "~1.4",
        "mockery/mockery": "0.9.*",
        "phpunit/phpunit": "~4.0",
        "phpspec/phpspec": "~2.1"
    },
    "autoload": {
        "files": [
            "app/Http/helpers.php",
            "app/Support/helpers.php"
        ],
        "classmap": [
            "database"
        ],
        "psr-4": {
            "App\\": "app/"
        }
    },
    "autoload-dev": {
        "classmap": [
            "tests/TestCase.php"
        ]
    },
    "scripts": {
        "post-install-cmd": [
            "php artisan clear-compiled",
            "php artisan optimize"
        ],
        "pre-update-cmd": [
            "php artisan clear-compiled"
        ],
        "post-update-cmd": [
            "php artisan optimize"
        ],
        "post-root-package-install": [
            "php -r \"copy('.env.example', '.env');\""
        ],
        "post-create-project-cmd": [
            "php artisan key:generate"
        ]
    },
    "config": {
        "preferred-install": "dist"
    }
}

Anyone help me how to get rid of this error and view my site successfully.

via Chebli Mohamed