I tried your monsterwriter site (nice looking app, by the way), and logged in with google. I don't see any option to "control where my data is stored". As far as I can tell as an end user, I've just created an account on your site.
Reading the Getting Started code, it only shows me configuring storage as a developer. Nothing about users doing any sort of bring-your-own storage, let alone firing one up from scratch with a friendly workflow.
What am I missing?
You don't miss anything.
The initial idea for linkedrecords was: I never want to write backend code and I want to build real time collaboration app. The realization that this way the user can choose its own backend came later. The idea never made it into MonsterWriter. But it would be very simple to add.
So the current implementation of MonsterWriter just hard codes the linkedrecords backend instead of prompting the user to pick one.
I don’t get it. Why did you title your hn submission after a feature that doesn’t exist?
Why not use that space to say something that your thing actually does? It’d save everyone a lot of confusion.