How to setup documentation for groovy in Netbeans 8

Solution for Netbeans 8.x ,Groovy 2.x (It will likely works with other version too)
Are you trying setup groovy documentation for Netbeans but you see this message:

"No groovy documentation found"

Well, this is how to do it correctly:
How add groovy documentation to Netbeans ?

1. Download Groovy documentation  from codehouse.org page (http://groovy.codehaus.org/Download) (if you download groovy as bundle,they you are ready have in installation 
2. Unzip to place where you keep documentation offline
3. Go to documentation folder and select groovy-2.x.x\html

Done. :)