We've been using https://c9.io for some time to run our training sessions for CakePHP, both the free cakephp training sessions and our standard (paid) cakephp training sessions. The service works great, but they provide a default workspace (Ubuntu 14.04 LTS and PHP 5.5.9) not compatible with the latest version of the CakePHP framework (3.4) requiring PHP 5.6+ (7+ strongly recommended). We wanted to provide an automated upgrade script for legacy cloud9 workspaces to PHP7.1 so we created a gist to upgrade the default workspace here
https://gist.github.com/steinkel/4eb1cb0b67ddb92f5d5b04646f470cd5
You can execute this gist using the raw link to the script, for example
source <(curl RAW_GIST_URL_HERE)
Enjoy!