How to use a LIKE Clause in Phalcon Object Document Mapper

Hi,

I am using monodb. I want to search collections with documents matching some keywords.

How do i use a LIKE clause. For e.g LIKE %keyword%

            $tags = Tags::find(array(
                 array("tagname" => $query),
                 "limit" => 100
            ));

For example, i would like to search tags with tagname attribute containing some keyword. Advice appreciated greatly!.

Thanks