(Quick Reference)
                docs
Purpose
Generates a user guide and Javadoc + Groovydoc API documentation for the current Grails project.
Examples
Add the plugin in your 
build.gradle:
apply plugin: "org.grails.grails-doc"
Now run the command
Description
Some projects, particular plugins, benefit from documentation explaining how they work. Grails comes with its own 
documentation engine based on a wiki syntax that can generate both HTML and PDF versions of a user guide, just like the one you are currently reading. If you have the source for a user guide in 
src/docs, then this command will automatically generate the corresponding HTML and PDF documents.
It's often useful to have API documentation as well. Since Grails is a mixed source framework, the command also generates both 
Javadoc (the standard format for Java documentation) and Groovydoc API references in HTML form.
The documentation is generated to the following directories:
- docs/api- Location of javadoc comments
- docs/gapi- Location of groovydoc comments
- docs/guide- Location of the user guide
- docs/ref- Location of the reference section of the user guide
Usage:
Arguments:
- --init- Create a template project documentation project (optional)
- --pdf- Create PDF output for project documentation (optional)
Fired Events:
- DocStart- Before documentation generation begins
- DocEnd- After documentation generation completes