Fix #122
Fix #122

Add jgroups to the documentation.

vietj/vertx,vert-x3/vertx-web-site,michel-kraemer/web-site,vietj/vertx,vert-x3/vertx-web-site,michel-kraemer/web-site,vietj/vertx,michel-kraemer/web-site,vert-x3/vertx-web-site