CommonMarker is a Ruby wrapper for libcmark-gfm, GitHub's fork of the reference
parser for CommonMark. It passes all of the C tests, and is therefore
spec-complete. It also includes extensions to the CommonMark spec as documented
in the GitHub Flavored Markdown spec, such as support for tables,
strikethroughs, and autolinking.

WWW: https://github.com/gjtorikian/commonmarker