Child theme

Hi,

I'me using the child theme the first time because I would like to make a change in the functions.php file.
Now, after changing my theme with your zip file my logo and the footer info are gone. I have no problem adding them back, but I hope this is the only issue I have.

I wanted to add to the functions.php the following code:

add_filter('pre_get_posts', 'query_post_type');
function query_post_type($query) {
  if(is_category() || is_tag()) {
    $post_type = get_query_var('post_type');
	if($post_type)
	    $post_type = $post_type;
	else
	    $post_type = array('post','review');
    $query->set('post_type',$post_type);
	return $query;
    }
}

in order to make also the categories and the tags searchable.

Could somebody help me and let me know where exactly should I paste that code? I've tried it and the site crashes.

Thanks.