laravel 5.1 access-control-origin for restFull api

Guys I'm developing restFull api using laravel 5.1.My endpoints are working correctly on postman. But when I integrate it with front-end it is getting following error.

XMLHttpRequest cannot load http://ift.tt/2gFV6Wq. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://ideahubfront.dev' is therefore not allowed access. The response had HTTP status code 500.

I've tried following methods.

(1) created core middle-ware.

 <?php

namespace App\Http\Middleware;

use Closure;

class Cors
{
    public function handle($request, Closure $next)
    {
        return $next($request)
            ->header('Access-Control-Allow-Origin', '*')
            ->header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS')
            ->header('Access-Control-Allow-Headers', 'Content-Type, Accept, Authorization, X-Requested-With');
    }
}

added it to kernal.php

<?php

namespace App\Http;

use Illuminate\Foundation\Http\Kernel as HttpKernel;

class Kernel extends HttpKernel
{
    /**
     * The application's global HTTP middleware stack.
     *
     * @var array
     */
    protected $middleware = [
        \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class,
        \App\Http\Middleware\EncryptCookies::class,
        \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
        \Illuminate\Session\Middleware\StartSession::class,
        \Illuminate\View\Middleware\ShareErrorsFromSession::class,
        \App\Http\Middleware\VerifyCsrfToken::class,
        \App\Http\Middleware\Cors::class,
    ];

    /**
     * The application's route middleware.
     *
     * @var array
     */
    protected $routeMiddleware = [
        'web' => \App\Http\Middleware\VerifyCsrfToken::class,
        'cors' => \App\Http\Middleware\Cors::class,
        'auth' => \App\Http\Middleware\Authenticate::class,
        'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
        'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
    ];
}

and to routes.php

Route::group(['middleware' => ['web', 'core'], 'prefix' => 'api/v1'], function(){

    // get single user by user id
    Route::get('getuserbyid/{user_id}', 'UserController@getSingleUserById');

    Route::post('users/register', 'UserController@register');

});

After that options requests worked. But post request still same.

(2) Added headers to controller return manually. Like this.

return response()->json([$user, $merchant], 200)
                ->header('Access-Control-Allow-Origin', '*')
                ->header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS')
                ->header('Access-Control-Allow-Headers', 'Cache-Control, Connection, Date, Server, Content-Type, User-Agent,  Accept, Referer, Authorization,Origin,  Accept-Encoding, Content-Length, Host, Connection,  X-Requested-With');

No luck. Guys please help me. I'm dying for this. My clients wants to see the registration. I'm stuck on this.

via Chebli Mohamed