Asciidoctor plantuml

By using one kind of diagram with asciidoctor-plantuml.js

playbook.yml

asciidoc:
  extensions:
    - asciidoctor-plantuml
  attributes:
    plantuml-server-url: 'http://www.plantuml.com/plantuml'

Table 1. some_page.adoc and the corresponding image in html page
	`[plantuml] ---- alice -> bob bob -> alice ----`