Add Docker support and automated downloads

[CaseyLabs]

Hi! Thanks so much for creating this utility, I've found it incredibly useful.

I've added Docker support for my own use, and thought you may be interested in it. Feel free to ignore or reject his PR if it doesn't fit your needs :-)

Usage:

• Place your cookies.txt in the ./docker folder

• Add a ./docker/urls.txt with the Spotify playlist URLs you want to automatically download.

• Run: docker compose up

• A docker image with Python + ffmpeg will be built, and will automatically download all playlists in urls.txt to the ./docker/downloads/ folder.

Thanks!

Demo:

[glomatico]

Nice addition and gif! But I'll pass this one.

[CaseyLabs]

All good! And thanks once again, super handy tool :-)