HOWTO add deck.js to an Asciidoctor project without resorting to git submodules

gistfile1.groovy

// You will need the VFS plugin
buildscript {
    repositories {
        jcenter()
    }

    dependencies {
        // Set your
        classpath 'org.asciidoctor:asciidoctor-gradle-plugin:0.7.0'
        classpath 'org.ysb33r.gradle:vfs-gradle-plugin:0.5'
        classpath 'commons-httpclient:commons-httpclient:3.1'    }
}

apply plugin: 'vfs' // NOTE: We still using old-style. From 0.6+ this will be org.ysb33r.vfs.

ext {
    asciidoctorBackendVersion = '0.1.4'
    downloadDir = new File(buildDir,'downloads')
    templateDir = new File(downloadDir,'asciidoctor-backends')
    deckjsDir   = new File(downloadDir,'deck.js')
    outDir      = new File(buildDir,'slides')
}

// We create special download task to pull from github
task download << {
    mkdir downloadDir
    vfs {
        cp "zip:https://github.com/asciidoctor/asciidoctor-backends/archive/asciidoctor-v${asciidoctorBackendVersion}.zip!asciidoctor-backends-asciidoctor-v${asciidoctorBackendVersion}",
                templateDir, recursive:true, overwrite:true
        cp "zip:https://github.com/imakewebthings/deck.js/archive/master.zip!deck.js-master",
                deckjsDir, recursive:true, overwrite:true
    }
}

// Asciidoctor task needs to know where deck.js template is located
asciidoctor {
    backend = 'html5'
    options = [
            'template_dir' : "${projectDir}/external/asciidoctor-backends/haml/deckjs",
    ]
    outputDir = outDir
}

// Completed slide deck needs to have deck.js included
asccidoctor.dependsOn 'copyDeckJs'
task copyDeckJs( type : Copy ) {
    from ('build/downloads') {
        include 'deck.js/**'
    }
    into outDir
}