Asciidoctor: Write Windows installation instructions

[graphitefriction]

Add a page to the documentation explaining how to install Asciidoctor on Windows using Chocolatey.

[PauloFrancaLacerda]

Very useful.
Having Asciidoc installed on Windows 7 was a real nightmare to me, since I'm not familiar to any platforms other than Windows, and the "Ruby gem" concept, Linux stuff, etc. Eventually, I've managed to get Ruby installed via Ruby Installer, but still had to struggle with some batch files and such.
After all, I still am not confident about the steps I've taken to make it work.

[mojavelinux]

I think the best way to install command line programs on Windows is Chocolatey. When taking that route, installation can be reduced to two commands (after installing Chocolately itself)

choco install ruby
gem install asciidoctor

Under the covers, choco actually uses Ruby Installer, but all the details are handled for you.

[mojavelinux]

There's also an AsciidoctorJ package for Windows (which installs the asciidoctorj command). The upside is that you can bypass the installation of Ruby. The downside is that Asciidoctor doesn't start as fast that way.

choco install asciidoctorj

That package is actually coming directly out of the AsciidoctorJ build, so it's guaranteed to be updated (assuming the AsciidoctorJ release process is configured correctly).