public function set_tokens($tokens)
{
$tokens = Utils::single_array($tokens);
$new_tokens = array_map(Method::create('\\Habari\\ACL', 'token_id'), $tokens);
$new_tokens = array_unique($new_tokens);
DB::delete('{post_tokens}', array('post_id' => $this->id));
foreach ($new_tokens as $token_id) {
DB::insert('{post_tokens}', array('post_id' => $this->id, 'token_id' => $token_id));
}
$this->tokens = $new_tokens;
}