in _plugins/markdown_tag.rb [7:15]
def render(context)
@f = File.read(File.join(Dir.pwd, @text))
if @f =~ /\A(---\s*\n.*?\n?)^((---|\.\.\.)\s*$\n?)/m
@f = $POSTMATCH
end
"#{Kramdown::Document.new(@f).to_html}"
end