Docker

Hello, guys. I'm a newbie with Docker! In my fresh project, I'm using laravel sail and admin is the backpack. I have one issue that's uploading images. I can't upload 1.5MB big images. I reading backpack docs, if you are having trouble uploading big images, please check your PHP extensions apcu. I can't find PHP extension apcu! So the question is "How to find PHP extension apcu through docker? Or is there another way to fix that? Thank you.