Document how to setup and use the AsciidoctorJ distribution

[mojavelinux]

Document in the AsciidoctorJ manual (i.e., the README) how to setup and use the AsciidoctorJ distribution. This is by far the easiest way to get Asciidoctor (via AsciidoctorJ) setup for end users.

We should recommend using gvm to install AsciidoctorJ.

$ curl -s get.gvmtool.net -o gvm-setup.sh && bash gvm-setup.sh

After reloading the terminal, gvm can be used to install the AsciidoctorJ distribution:

$ gvm install asciidoctorj

This will make the asciidoctorj command available, which is a drop-in replacement for the asciidoctor command:

$ asciidoctorj -V

The command provides support for the following backends out of the box:

• html (html5)
• docbook (docbook5)
• docbook45
• pdf
• epub3

For example, you can convert a document to PDF using:

$ asciidoctorj -b pdf sample.adoc

[msgilligan]

This is a great way to get started with AsciidoctorJ. Although it's now:

 $ sdk install asciidoctorj