We should document the existance of `new_resource`
In #1097, we refer to the new_resource
method which is useful when building out new records in a controller. But it isn't referenced anywhere.
We might like to answer:
- What problem does it solve?
- How do you use it?
It'd be best if we added it to a "Customising Administrate" or "Internals" section, or similar.