public function store(Request $request)
    {
        $this->authorize('create', Notification::class);

        $this->validate($request, [
            'email'   => 'required|email|exists:users,email',
            'subject' => 'required|min:10|max:30',
            'message' => 'required|max:1500',
        ]);

        $me = User::findOrFail(Auth::id());

        User::where(['email' => $request->email])->first()
                    ->notify(new MessageNotification($request->subject, $request->message, $me));

        return redirect()->route('laralum::notifications.index')->with('success', __('laralum_notifications::general.notification_sent'));
    }