functions.php

function add_membership_support() {
  $labels = array(
    'name'               => _x( 'DTS Premium', 'post type general name', 'sage' ),
    'singular_name'      => _x( 'Premium Post', 'post type singular name', 'sage' ),
    'menu_name'          => _x( 'Premium Posts', 'admin menu', 'sage' ),
    'name_admin_bar'     => _x( 'Premium Post', 'add new on admin bar', 'sage' ),
    'add_new'            => _x( 'Add New', 'product', 'sage' ),
    'add_new_item'       => __( 'Add New Premium Post', 'sage' ),
    'new_item'           => __( 'New Premium Post', 'sage' ),
    'edit_item'          => __( 'Edit Premium Post', 'sage' ),
    'view_item'          => __( 'View Premium Post', 'sage' ),
    'all_items'          => __( 'All Premium Posts', 'sage' ),
    'search_items'       => __( 'Search Premium Posts', 'sage' ),
    'parent_item_colon'  => __( 'Parent Premium Posts:', 'sage' ),
    'not_found'          => __( 'No premium posts found.', 'sage' ),
    'not_found_in_trash' => __( 'No premium posts found in Trash.', 'sage' )
  );
  $args = array(
    'labels'            => $labels,
    'public'            => true,
    'label'             => 'Premium Posts',
    'has_archive'       => true,
    'menu_icon'         => 'dashicons-lock',
    'capability_type'   => 'post',
    'supports'          => array(
                                'title',
                                'editor',
                                'author',
                                'thumbnail',
                                'excerpt',
                                'trackbacks',
                                'custom-fields',
                                'comments',
                                'revisions'        
                            ),
    'rewrite'           => array('slug' => 'premium')
  );
  register_post_type( 'premium', $args );
  register_taxonomy_for_object_type( 'premium-category', 'premium' );
}
add_action( 'init', 'add_membership_support' );



// Register Custom Taxonomy
function premium_category() {

    $labels = array(
        'name'                       => _x( 'Premium Categories', 'Taxonomy General Name', 'text_domain' ),
        'singular_name'              => _x( 'Premium Category', 'Taxonomy Singular Name', 'text_domain' ),
        'menu_name'                  => __( 'Categories', 'text_domain' ),
        'all_items'                  => __( 'All Items', 'text_domain' ),
        'parent_item'                => __( 'Parent Item', 'text_domain' ),
        'parent_item_colon'          => __( 'Parent Item:', 'text_domain' ),
        'new_item_name'              => __( 'New Item Name', 'text_domain' ),
        'add_new_item'               => __( 'Add New Item', 'text_domain' ),
        'edit_item'                  => __( 'Edit Item', 'text_domain' ),
        'update_item'                => __( 'Update Item', 'text_domain' ),
        'view_item'                  => __( 'View Item', 'text_domain' ),
        'separate_items_with_commas' => __( 'Separate items with commas', 'text_domain' ),
        'add_or_remove_items'        => __( 'Add or remove items', 'text_domain' ),
        'choose_from_most_used'      => __( 'Choose from the most used', 'text_domain' ),
        'popular_items'              => __( 'Popular Items', 'text_domain' ),
        'search_items'               => __( 'Search Items', 'text_domain' ),
        'not_found'                  => __( 'Not Found', 'text_domain' ),
        'no_terms'                   => __( 'No items', 'text_domain' ),
        'items_list'                 => __( 'Items list', 'text_domain' ),
        'items_list_navigation'      => __( 'Items list navigation', 'text_domain' ),
    );
    $args = array(
        'labels'                     => $labels,
        'hierarchical'               => true,
        'public'                     => true,
        'show_ui'                    => true,
        'show_admin_column'          => true,
        'show_in_nav_menus'          => true,
        'show_tagcloud'              => true,
    );
    register_taxonomy( 'premium-category', array( 'premium' ), $args );

}
add_action( 'init', 'premium_category', 0 );