Self hosted: how to add an existing user into another organization

[mydnic]

I asked this question on discord but didn't get any reply so I'll try here.

We recently moved all our website from plausible to Rybbit and thanks to the Organization system, we were able to kinda split our websites into multiple organizations to better manage our different projects, clients and companies.
Anyway, I created a user for my coworker (since there's no invite button) into our main organization, and I created another organization where I need to give him access to. However this doesnt' seem possible at the moment ?

Is there any way to achieve this ? Even a hacky/database manual change way is fine

Our Rybbit instance run on docker

Thanks a lot