Add comment on updating the app skeleton
Add comment on updating the app skeleton

Refs: https://github.com/cakephp/app/issues/462
QoboLtd/project-template-cakephp,QoboLtd/project-template-cakephp,makallio85/fish-diary,QoboLtd/project-template-cakephp,makallio85/fish-diary,QoboLtd/project-template-cakephp,makallio85/fish-diary,QoboLtd/project-template-cakephp