Best free resources to learn Grails

Hello guys Grails is more famous in now days, Grails is an open source web application framework that uses the Groovy programming language.Grails make our web-developments easy and fast.I am new in groovy and grails technologies,so i have face lot of problems in my project because i am new and don't know enough about groovy and grails and in grails own web-site https://grails.org/ there is not enough tutorials of  grails where you find easily solutions of your problems and also not have a good documentation because its new so i think that's why there is not enough stuff for learn in there documentation but i found some tutorials site is very useful and i want to share those web site with you, so guys below is some useful tutorial websites, i hope this stuff helpful to you.

http://www.vogella.com/tutorials/Grails/article.html
http://www.grailsexample.net/
http://www.jellyfishtechnologies.com/category/grails/grails-2-3-0/
http://stackoverflow.com/questions/tagged/grails
http://techmytalk.com/2013/08/07/grails-gorm/
http://www.ibm.com/developerworks/views/java/libraryview.jsp?search_by=mastering+grails
http://pleac.sourceforge.net
http://www.infoq.com/minibooks/grails-getting-started

Thanks guys hope its helpful blog please  comments.