Passing raw device to container

I’m connecting an external hard disk to my Pi 3. The disk is formatted as “Mac OS Extended”, also known as HFS+ which my container has the appropriate drivers to use. A SO answer wants me to use the device flag when executing docker run, how do I customize this using resin

Docker supports adding/passing through devices to a container:
docker run --device=/dev/sdb
Stack Overflow

Nevermind, turns out the containers are run in privileged mode and have access to devices already