How to add an additional "book" to the App?

In version 3.0 it was possible to add books to the Archive App by importing .glcatalog files.
those files looked like that:
{
"name": "nameofthe book",
"url": "http://www.urlof the book"
}
The same files do not work any more in V4.0.
How do we have to change the syntex?

Gospel Library 4 uses a new, rich HTML5 content format. The older content format is no longer supported.