Allow specifying requirements file location

For scikit-image, we host the various versions of our documentation inside a single repo. We do this so that they render as https://scikit-image.org/docs/0.16.x/, https://scikit-image.org/docs/0.15.x/, etc.

We would like to add binder links to our example notebooks, but for each version of the docs, we need a different version of scikit-image. So, we would like to launch an image that fetches its requirements from, say, 0.16.x/requirements.txt.

Currently, requirements can be specified per repo, or per branch, but no specific location can be provided.

What do you think about allowing specifying the requirements path, instead of expecting it in a fixed location?

[stefanv]

(You can go ahead and close the issue, if you want. I still think this would be a valuable feature: it would prevent people from having to jump through post-build hoops like described above, and I don’t think it’s unreasonable to want to host multiple setups in one repo.)

Thanks again for helping us out with a solution!

[betatim]

The scikit-image gallery now has binder badges so closing this.