Mage2\Catalog\Controllers\ReviewController::store PHP Method

    public function store(ReviewRequest $request)
    {
        if (!Auth::check()) {
            $user = User::where('email', '=', $request->get('email'))->get()->first();
            if (null === $user) {
                $request->merge(['password' => str_random($length = 6)]);
                $user = User::create($request->all());
            }
        } else {
            $user = Auth::user();
        }
        $request->merge(['user_id' => $user->id]);
        Review::create($request->all());
        return redirect()->back();
    }