Laravel4.2 Class 'Krucas\Notification\NotificationServiceProvider' not found - laravel

Question

My make up a project by laravel4.2;
(1)first,I install the "edvinaskrucas/notification"
in my composer.json in the require-line like this:
"require": {
"laravel/framework": "4.2.*",
"cartalyst/sentry":"2.1.4",
"fzaninotto/faker":"1.5.*#dev",
"edvinaskrucas/notification": "4.0.0"
},
(2)second, I join two lines codes into my laravel config file config/app.php below each last line like this :
'providers' => array(
'Illuminate\Foundation\Providers\ArtisanServiceProvider',
'Illuminate\Auth\AuthServiceProvider',
'Illuminate\Cache\CacheServiceProvider',
'Illuminate\Session\CommandsServiceProvider',
'Illuminate\Foundation\Providers\ConsoleSupportServiceProvider',
'Illuminate\Routing\ControllerServiceProvider',
'Illuminate\Cookie\CookieServiceProvider',
'Illuminate\Database\DatabaseServiceProvider',
'Illuminate\Encryption\EncryptionServiceProvider',
'Illuminate\Filesystem\FilesystemServiceProvider',
'Illuminate\Hashing\HashServiceProvider',
'Illuminate\Html\HtmlServiceProvider',
'Illuminate\Log\LogServiceProvider',
'Illuminate\Mail\MailServiceProvider',
'Illuminate\Database\MigrationServiceProvider',
'Illuminate\Pagination\PaginationServiceProvider',
'Illuminate\Queue\QueueServiceProvider',
'Illuminate\Redis\RedisServiceProvider',
'Illuminate\Remote\RemoteServiceProvider',
'Illuminate\Auth\Reminders\ReminderServiceProvider',
'Illuminate\Database\SeedServiceProvider',
'Illuminate\Session\SessionServiceProvider',
'Illuminate\Translation\TranslationServiceProvider',
'Illuminate\Validation\ValidationServiceProvider',
'Illuminate\View\ViewServiceProvider',
'Illuminate\Workbench\WorkbenchServiceProvider',
'Way\Generators\GeneratorsServiceProvider',
'Cartalyst\Sentry\SentryServiceProvider',
'Krucas\Notification\NotificationServiceProvider' ***--this new join in***
),
'aliases' => array(
'App' => 'Illuminate\Support\Facades\App',
'Artisan' => 'Illuminate\Support\Facades\Artisan',
'Auth' => 'Illuminate\Support\Facades\Auth',
'Blade' => 'Illuminate\Support\Facades\Blade',
'Cache' => 'Illuminate\Support\Facades\Cache',
'ClassLoader' => 'Illuminate\Support\ClassLoader',
'Config' => 'Illuminate\Support\Facades\Config',
'Controller' => 'Illuminate\Routing\Controller',
'Cookie' => 'Illuminate\Support\Facades\Cookie',
'Crypt' => 'Illuminate\Support\Facades\Crypt',
'DB' => 'Illuminate\Support\Facades\DB',
'Eloquent' => 'Illuminate\Database\Eloquent\Model',
'Event' => 'Illuminate\Support\Facades\Event',
'File' => 'Illuminate\Support\Facades\File',
'Form' => 'Illuminate\Support\Facades\Form',
'Hash' => 'Illuminate\Support\Facades\Hash',
'HTML' => 'Illuminate\Support\Facades\HTML',
'Input' => 'Illuminate\Support\Facades\Input',
'Lang' => 'Illuminate\Support\Facades\Lang',
'Log' => 'Illuminate\Support\Facades\Log',
'Mail' => 'Illuminate\Support\Facades\Mail',
'Paginator' => 'Illuminate\Support\Facades\Paginator',
'Password' => 'Illuminate\Support\Facades\Password',
'Queue' => 'Illuminate\Support\Facades\Queue',
'Redirect' => 'Illuminate\Support\Facades\Redirect',
'Redis' => 'Illuminate\Support\Facades\Redis',
'Request' => 'Illuminate\Support\Facades\Request',
'Response' => 'Illuminate\Support\Facades\Response',
'Route' => 'Illuminate\Support\Facades\Route',
'Schema' => 'Illuminate\Support\Facades\Schema',
'Seeder' => 'Illuminate\Database\Seeder',
'Session' => 'Illuminate\Support\Facades\Session',
'SoftDeletingTrait' => 'Illuminate\Database\Eloquent\SoftDeletingTrait',
'SSH' => 'Illuminate\Support\Facades\SSH',
'Str' => 'Illuminate\Support\Str',
'URL' => 'Illuminate\Support\Facades\URL',
'Validator' => 'Illuminate\Support\Facades\Validator',
'View' => 'Illuminate\Support\Facades\View',
'Sentry' => 'Cartalyst\Sentry\Facades\Laravel\Sentry',
'Notification' => 'Krucas\Notification\Facades\Notification' ***-->and this new***
),
(3) when i refresh the firefox after "dump-autoload the composer.json", then comes my question:
it says :
Symfony \ Component \ Debug \ Exception \ FatalErrorException (E_ERROR)
Class 'Krucas\Notification\NotificationServiceProvider' not found!
What can I do to resolve this problem? Hope someone who sees this can help me.

Answer 1

To actually install a package you have to run composer update after adding it to composer.json.
composer update will detect the package added to composer.json and download the source.

Answer 2

Comment those two "joins" and do a composer dump-autoload and after uncomment those lines