anchor.diff:  ----
   <1> append below the line: `apply plugin: 'org.asciidoctor.gradle.asciidoctor'`
   
  +The following attributes are automatically set by the `asciidoctor` task:
  +
  + * project-name : matches `$project.name`
  + * project-version: matches `$project.version` (if defined). Empty String value if undefined
  + * project-group: matches `$project.group` (if defined). Empty String value if undefined
  +
  +These attributes may be overridden by explicit user input.
  +
   You may need to include extra content into the head of the exported document.
   For example, you might want to include jQuery inside the `<head>` element of the HTML export.
   To do so, first create a docinfo file `src/docs/asciidoc/docinfo.html` containing the content to include, in this case the `<script>` tag to load jQuery.
  
positive.code: .Properties
  [horizontal]
  logDocuments:: a boolean specifying if documents being processed should be logged on console. Type: boolean. Default: `false`.
  
  .Methods
  [horizontal]
  
negative.code: attributes:: a Map specifying various document attributes that can be sent to Asciidoctor
    Use `attributes` to append, Use `setAttributes` or `attributes=` to overwrite.
  
  === Sources
  
  By default the plugin will search for sources under `sourceDir`. Sources may have any of the following extensions in
  order to be discovered:
  
  * .asciidoc
  * .adoc
  * .asc
  * .ad
  
  To select only certain files use the `sources` method. This takes a closure which in turn configures an internal
  {http://www.gradle.org/docs/current/javadoc/org/gradle/api/tasks/util/PatternSet.html}[PatternSet]
  
  [source,groovy]
  .build.gradle
  ----
  sources {
    include 'toplevel.adoc'
  }
  ----
  
  Source files are resolved relative to `sourceDir`.  Source files are also not allowed to start with an underscore.
  
  === Handling additional files
  
  Some backends require that additional files be copied across. The most common example are images for HTML backends. For
  this the `resources` method is used. It is provided with a closure that configures an internal
  {http://www.gradle.org/docs/current/javadoc/org/gradle/api/file/CopySpec.html}[CopySpec]
  
  [source,groovy]
  .build.gradle
  ----
  resources {
    from('src/resources/images') {
      include 'images/**/*.png'
      exclude 'images/**/notThisOne.png'
    }
  
    from( "${buildDir}/downloads" ) {
      include 'deck.js/**'
    }
  }
  ----
  
  Files will be copied to below `${outputDir}/${backend}` (or just `${outputDir}` if `separateOutputDirs=false`)
  
  Unlike `sourceDir` files can be copied from anywhere in the filesystem.
  
  If `resources` is never set, the default behaviour is as if the following was called
  [source,groovy]
  .build.gradle
  ----
  resources {
    from(sourceDir) {
      include 'images/**'
    }
  }
  ----
  
  If you do not want this behaviour, then it can be turned off by doing
  [source,groovy]
  .build.gradle
  ----
  resources {}
  ----
  
  === Options & Attributes
  The following options may be set using the task's `options` property
  
   * header_footer - boolean
  