Triggered after relationship is created between two GUID.

~~~
<?php
function my_component_init(){
ossn_register_callback('relation', 'add', 'my_component_cb');
}
function my_component_cb($callback, $type, $params){
//$params[to], $params[from], $params[type]
}
ossn_register_callback('ossn', 'init', 'my_component_init');
~~~