Merge pull request #21 from rappleg/master

Updated meeting date to 3rd Tuesday of the month.
Merge pull request #22 from rappleg/master

Updated to use new Meetup group instead of old Google mailing list.
Merge pull request #23 from rappleg/master

Add link to meetup group in Readme.
Upgrade to Grails 2.2.4
Add wrapper for Grails 2.2.4