Books may be organized by genre, series, or tag. The tags that books are organized by are not the same tags that posts are organized by.
No versions of Mooberry Book Manager add category organization. Is your goal to include books on the page that lists your categories?
This code should do that. Best place to put this code is in the functions.php
file of your child theme. ( see https://www.smashingmagazine.com/2016/01/create-customize-wordpress-child-theme/ if you don’t know what a child theme is or how to create one.)
add_action('init', 'mbdb_add_category_to_books', 20);
function mbdb_add_category_to_books() {
register_taxonomy_for_object_type( 'category', 'mbdb_book');
}
add_filter( 'pre_get_posts', 'mbdb_add_book_to_category_archive' );
function mbdb_add_book_to_category_archive( $query ) {
if( is_category() && $query->is_main_query() && empty( $query->query_vars['suppress_filters'] ) ) {
$post_types = array();
if ( !empty($query->query_vars['post_types'] ) ) {
$post_types = $query->query_vars['post_types'];
}
$post_types = $post_types + array('mbdb_book', 'post');
$query->set( 'post_type', $post_types );
return $query;
}
}
If you also want to display the category on your book page, that is some additional code and it will depend where you want to display it.
Hope this helps!