You want to use the register_taxonomy_for_object_type function documented here
add_action('init','fix_my_tax');
function fix_my_tax(){
register_taxonomy_for_object_type('taxonomy', 'post_type');
}
You want to use the register_taxonomy_for_object_type function documented here
add_action('init','fix_my_tax');
function fix_my_tax(){
register_taxonomy_for_object_type('taxonomy', 'post_type');
}