Binderhub: Document `filepath` and `urlpath` launch link parameters

[raffadrummer]

Is there a reason why the deep/direct link fix discussed in https://github.com/binder-project/binder/issues/68 and https://github.com/binder-project/binder-web/issues/6 is not working anymore?

[betatim]

You can now open files directly with a link like

https://mybinder.org/v2/gh/binder-examples/requirements/master?filepath=index.ipynb

[mapio]

That's interesting! Could such info be added to the docs? Apparently filepath is never mentioned…

https://binderhub.readthedocs.io/en/latest/search.html?q=filepath

[betatim]

It would be a good addition to the docs and a good first issue if you want to tackle it.

A good place to add it is https://binderhub.readthedocs.io/en/latest/api.html#provider

As well as expanding on what is already there in https://mybinder.readthedocs.io/en/latest/introduction.html?highlight=filepath (repo: for that page is https://github.com/jupyterhub/binder)

[sgibson91]

Capturing a conversation from gitter that I think is relevant to this issue.

Using urlpath=/terminals/1 will directly open a terminal on launch.