feat: postgresql store

[milancermak]

Resolves #5

I've modeled the crate on the SQLite one.

On the DB side, the crate is relying on the pgvector extension. It creates an HSNW index and uses the cosine distane operator to compare embeddings.

Please let me know it this looks ok or if there are any parts of the code that should be changed.

[0xMochan]

Thanks for your contribution, nearly done with my review but I'll go ahead and approve and run the workflow. I think you might need to cargo fmt and pass cargo clippy as well.

[b0xtch]

Hey great work, any update on this?

[0xMochan]

Hey great work, any update on this?

I'm still in my review, I got wrapped up in some other responsibilities, will get it out ASAP!

[0xMochan]

Apologies for the delay on this review! Mostly looking good, a couple of changes I've requested here.

One note: I noticed that 'static was used a good bit here which was likely inherited from the sqlite implementation. I think this is due to how the connection requires an closure with an async block which makes borrowing and using such things really odd.

Recently, proper async closures which will get into Rust stable sometime in 2025 which should help us alleviate our usage of 'static here (i think!)

[milancermak]

Thanks for the review. I'm still in holiday mode until New Year's, will address the comments on Jan 2 or 3.

[milancermak]

Hey @0xMochan ready for another round. I've addressed the comments you brought up, optimistically resolved the ones I think are done, but feel free to reopen if you think otherwise.