Grails integration for Url-Rewrite.

1. Add the plugin to your project's grails-app/conf/BuildConfig.groovy:

   compile ":url-rewrite:1.0-SNAPSHOT"

2. Add a urlrewrite.xml file to web-app/WEB-INF/

Further configuration of urlrewrite.xml can be done as per the urlrewrite documentation.

TODO                | in progress                | DONE
                                                   inject the url rewrite rules at the top of web.xml

Could add a groovy DSL for defining rewrite rules... but seems a bit pointless.