Szurubooru backend rewrite

[liamw1]

About six months ago I started working on a total rewrite of the backend on my fork with a focus on improving performance. It's finally far enough along that I'm comfortable distributing a first release. I wouldn't say it's production ready, but it should be fine for personal use.

I've made a number of changes and improvements to the backend:

• Most queries are 2-10x faster
• Significantly faster startup time
• Reverse image search is slightly better at discerning similar images from dissimilar ones
• Reverse image search is faster and more thorough
• Improved tag implication/suggestion cyclic dependency detection
• Post navigation via neighbors respects sorting
• Ability to sort posts by pool count, uploader, aspect ratio, and safety
• Ability to filter tags that have a specific implication or suggestion
• Server no longer locks up when mass-deleting related posts
• Separate secrets for hashing passwords and post ids (security: fix secret leak #580)

If you're interested in trying it out, I've also created a script to convert a Szurubooru database into one compatible with my fork. Though this has some limitations which are noted in the conversion guide.

Questions and contributions are welcome.

[neobooru]

Looks very cool, though I haven't fully explored it yet. Are the known limitations in https://github.com/liamw1/oxibooru/blob/master/doc/CONVERSION.md the only missing/different features, or are there other not-yet-implemented features?

[liamw1]

That basically covers it. The API is almost fully implemented; the only unimplemented feature is listing snapshots. Password reset requests are technically implemented but are unlikely to actually work because they are entirely untested (I haven't set up a SMTP server to test them yet).