Because I couldn’t find the information anywhere else, if you want to
use maven with Grails 1.2 snapshot, use:
mvn org.apache.maven.plugins:maven-archetype-plugin:2.0-alpha-4:generate -DarchetypeGroupId=org.grails -DarchetypeArtifactId=grails-maven-archetype -DarchetypeVersion=1.2-SNAPSHOT -DgroupId=uk.org.catnip -DartifactId=armstrong -DarchetypeRepository=http://snapshots.maven.codehaus.org/maven2