Pulling Docker image from private protected repository within bash script

Question

I am trying to write a bash script to automatize the setup of a multi-containers environment. Each container is built from images pulled from a private protected repository.

The problem is that when the script calls for docker-compose up for the first time, access to the repository is denied, like if it does not know I have properly done docker login before running the script. If I docker pull an image manually, that very image is no longer a problem when the script tries to build its container. But when it has to docker pull on its own from a Dockerfile definition, it gets access denied.

Considering that I would like this script to be portable to other devs' environments, how can I get it to be able to access the repository using the credentials each dev will have already set on its computer with docker login?

Thanks a lot!