Supabase auth

[gatewaynode]

What kind of change does this PR introduce?

SupaBase specific feature addition and documentation update.

What is the current behavior?

Only works with the PostgRest JWT only auth scheme.

What is the new behavior?

This addition adds support for the Kong gateway API key in SupaBase as an alternate authorization trait (supa_auth()). Documentation also captures the API path needed.

Additional context

New doc and unit tests added. All tests passing locally.

[soedirgo]

Thanks for the PR!

This repo is for PostgREST in general, not specific to Supabase, so I don't think it's apt to have supa_auth(). As a workaround, in postgrest-js you'd pass the headers as an optional parameter in the constructor, but this breaks the API in Rust so my suggestion is to have a header() method in the builder that does self.headers.insert(key, value). WDYT?

[gatewaynode]

Rewrite as a generic header injection method? I think that's a fair compromise. I would like the documentation to specify how that would work with SupaBase as the example though.

[soedirgo]

I would like the documentation to specify how that would work with SupaBase as the example though.

Yup! That's perfectly fine.

[gatewaynode]

We can close this as I've created the compromise solution in #26