Passing options to commonmarker

I am using commonmarker as markdown_engine for my middleman site.

I want to pass commonmarker option UNSAFE => true. How do I go about it?

Sorry for the incomplete information. I am using commonmarker via html-pipeline. I got the solution now. I am now using the following configuration (I had to add :unsafe => true in the context).

    def prepare
      @engine = HTML::Pipeline.new [
        HTML::Pipeline::MarkdownFilter,
        HTML::Pipeline::EmojiFilter,
        HTML::Pipeline::RougeFilter,
        HTML::Pipeline::TableOfContentsFilter
      ], {:asset_root => "/", :gfm => true, :unsafe => true, :line_numbers => true, :config => Sanitize::Config::RELAXED}
    end

Did you ever get anywhere with this? I want to use CommonMarker to process my .md files, and got as far as:

set :markdown_engine, "CommonMarker"

But I just get blank files.