Remotes elements should be put into the Dockerfile

[ColinFay]

By default, {golem} is used as a dependency to the created app.

But the add_dockerfile() function only parses the Imports from DESCRIPTION, so doesn't install Remotes elements

[ColinFay]

Handled by using install_local() on app.tar.gz

[aftonsteps]

Sorry if this is a silly question, but how would you use install_local() in this case? I can see how to locally include a tar.gz for some library along with the app's other local files, and then use install_local() somewhere in the app's code to install from that tar.gz. But I think think this would install that library every time that app starts up, rather than just once when the container is created. Is there a way to specify installation from the tar.gz somewhere in the Dockerfile?