✨ Feature parity: Subscriptions saved across devices/browsers (self hosted instance only)

[olinorwell]

How does this feature work on Reddit?

I can log into Reddit from any browser or device and it 'has remembered' which subreddits I read (all 200 odd of them).

Describe how this could be implemented into Libreddit

Currently, Libreddit uses cookies to save which subreddits are subscribed to. I self-host Libreddit, and the same information could be in a simple text file inside the Docker container where I'm running Libreddit.

Describe alternatives you've considered

One alternative is to subscribe to each new subreddit I discover and want to follow on each device I use. This isn't ideal and with 3 computers and a couple of mobile devices it isn't practical.

Additional context / screenshot

I appreciate this feature doesn't make sense on a public Libreddit instance. However, this feature makes complete sense on a privately self-hosted Libreddit instance. I believe this feature should be very straightforward to implement as effectively we're just pointing Libreddit to a cookie text file inside the docker container rather than one held by the browser. Without the feature, if I move to a different computer and view my private Libreddit instance, I lose everything and have to resubscribe to everything.