Add a package to box

Hi,
I have a rails app, and would like to install the vips package on the box. I believe thats the libvips-dev or something like that.
What is the way to do that? Do I need a docker file for that or can I add that information to the fly.toml?

Thx,
Grzegorz

I just ran into this.

I solved it by adding libvips to the Dockerfile. Specifically, in this line:

ARG DEPLOY_PACKAGES="postgresql-client file vim curl gzip libsqlite3-0 libvips"