Initially, the first project before IBA was a Documenter, the markdown editor, or perhaps one day*, the powerhouse for drafting the contents you wish to create, however our means, which as of date March 21, 2018, being my personal development skills and free-time here and there, has been too limited to establish and jumpstart the project ...
but till that day, here you go:
You can also use pandoc:
pandoc -f markdown -t docx file.md -o file.docx
One advantage compared to textutil is that the output uses paragraph styles. You can also use styles from an existing file with --reference-docx file.docx.'