public function bid(Request $request)
{
$this->validate($request, ['id' => 'required', 'prev' => 'required', 'bid' => 'required|greater_than_field:prev']);
$auction = Auction::findOrFail($request->id);
$auction->price = $request->bid;
$auction->save();
$user = Auth::user();
$bidder = new Bidder();
$bidder->user()->save($user);
$bidder->auction()->associate($auction);
$bidder->price = $request->bid;
$bidder->save();
return redirect('/art');
}
