Having trouble with docker-compose up?

Try docker-compose down && docker-compose build. Good chance that will clear it up.

Adding a dependency from npm

Say you have a dependency called fantasy-land

The procedure is:

docker-compose run web "pnpm install && pnpm install fantasy-land"
docker-compose down
docker-compose up --build

Make sure that you have the dependency in the new version, and then commit package.json and pnpm-lock.yaml.