I thought there will be some automatic building script for flatpaks,
so the maintainers doesn't need to do it by themselves.
Is this automatization now dropped?
One level of automation is 'fedmod rpm2flatpak' which automatically figure out dependencies and creates a module definition file which says what Fedora packages need to be rebuilt for inclusion in your Flatpak. This module definition file can often be used without any further editing. 'fedmod rpm2flatpak' also creates a container definition file (container.yaml) which includes, among other things, the permissions for the application. This does require manual editing, and, unless the permission settings can be copied from an existing Flatpak of the application, usually some testing to get right.
There's really no way to get around that level of human involvement - to define the permissions for the app and check that the result works.
The other planned type of automation is automated rebuilds. We want to be to the point where when there is an update for an included package, the Flatpak is automatically rebuilt, a Bodhi update for the updated Flatpak is filed, and email is sent to the maintainer requesting that they test the new Flatpak. This does not exist yet, but the plan is to have it before Fedora 30. For now, we need to build out the set of Flatpaks so we understand how the system is working for maintainers and users.