Upload support

[liamdawson]

Sometimes I want to download files from a remote Docker container running on a server. I get access to the container directly, and don't have SCP access or similar options to pull the file down to my machine. It would be super convenient if I could run this on my local machine, and do an authenticated cURL PUT request from the container to push the file to my local machine.

Would you consider adding upload support, preferably for authenticated users?