I tried to use this solution on the newer versions of Wordpress / Angular and it wouldn't work, but I found another way to make this happen. In the file, register-portfolio.php located in /includes/admin, I went to the following lines of code:
$args = array(
'labels' => $labels,
'public' => true,
'show_ui' => true,
'capability_type' => 'post',
'hierarchical' => false,
'rewrite' => array('slug'=>$slugRule,'with_front'=>true),
'query_var' => true,
'show_in_nav_menus'=> false,
'supports' => array('title','thumbnail','excerpt','editor','comments')
I changed the final line to read:
'supports' => array('title','thumbnail','excerpt','editor','comments','author')
Maybe this will be useful to others!