Docs are incomplete for one-to-many relations #721
Description
It would be great to mention in the documentation that the foreign UUID key of a child element is mandatory to have as a HIDDEN field a relation editor widget work properly in a parent feature form. I just spent about 4 hours tinkering with a project to understand why the one-to-many wasn't working properly within the mobile app while seeming to work fine in QGIS. I think many users would intuitively remove the foreign UUID key from the drag and drop designer, but it really has to be there for things to work.