public function postSignUp(Request $request)
{
$this->validate($request, [
    'email' => 'required|email|unique:users',
    'first_name' => 'required|max:120',
    'password' => 'required|min:4'
]);

$email = $request['email'];
$first_name = $request['first_name'];
$password = bcrypt($request['password']);

$user = new User();
$user->email = $email;
$user->first_name = $first_name;
$user->password = $password;

$user->save();

Auth::login($user);

return redirect()->route('dashboard');
}

<div class="alert alert-danger">
    <ul>
    @foreach ($errors->all() as $error)
        <li>{{ $error }}</li>
    @endforeach
   </ul>
</div>

Route::group(['middleware' => ['web']], function ()
{
Route::post('/signup', ['uses' => 'UserController@postSignUp', 'as' =>    'signup']);
Route::post('/signin', ['uses' => 'UserController@postSignIn', 'as' => 'signin']);
Route::get('/dashboard', ['uses' => 'UserController@getDashboard', 'as' =>   'dashboard']);
});