public function showInvoices()
{
$group = User::where('customer_id', Auth::user()->customer->id)->lists('id')->toArray();
$invoices = Order::paid()->whereIn('user_id', $group)->groupBy('invoice_nr')->selectRaw('invoice_nr, sum(total_price) as total_price')->get();
return view('account.invoices', compact('invoices'));
}
