This is a tutorial that teaches Thom Frühwirth's CHR system that comes as part of the standard **SWI-Prolog distribution.
Install asciidoctor
make a directory /etc/asciidoc/themes/pathways
copy the contents of the pathways directory under the project root into this dir
to rebuild the web pages, compile all .adoc files with asciidoc
asciidoc -a stylesheet=themes/pathways/style.css -a stylesdir=themes/pathways/ final.adoc >final.html
and serve.