https://github.com/grails-plugins/grails-tomcat-plugin
Previously there were two separate repos for the Tomcat Grails plugin. This repo was for Tomcat 8 and there was a separate repo for Tomcat 7.
Going forward, all versions of the plugin will be maintained in the original Tomcat repo. The master branch in that repo is for Tomcat 8 and the 7.x branch is for Tomcat 7.