src/AuthEmailServiceProvider.php
public function boot(Validator $validator)
    {
        /**
         * Better safe than sorry, check Laravel's documentation
         * https://laravel.com/docs/5.4/migrations#creating-indexes
         * for details
         */
        Schema::defaultStringLength(191);

        /**
         * Registering commands with artisan
         */
        if ($this->app->runningInConsole()) {
            $this->commands([
                AuthEmail::class,
            ]);
        }

        /**
         * Register custom Validator for alphanumeric with spaces
         */
        $validator->extend('alpha_spaces', function ($attribute, $value) {
            return preg_match('/^[\pL\s]+$/u', $value);
        });
    }
public function boot(Validator $validator)
    {
        /**
         * Better safe than sorry, check Laravel's documentation
         * https://laravel.com/docs/5.4/migrations#creating-indexes
         * for details
         */
        Schema::defaultStringLength(191);

        /**
         * Registering commands with artisan
         */
        if ($this->app->runningInConsole()) {
            $this->commands([
                AuthEmail::class,
            ]);
        }

        /**
         * Register custom Validator for alphanumeric with spaces
         */
        $validator->extend('alpha_spaces', function ($attribute, $value) {
            return preg_match('/^[\pL\s]+$/u', $value);
        });
    }
Perform post-registration booting of services.

@param Validator $validator
@return void