Here is how to use composer on Clever Cloud. Basically, you have to create your own composer.json at the root of the application and its dependencies will be installed.
Here is our documentation about composer
If you need a specific version of composer, you can also commit your own composer.phar
at the root of the application and it will be used to install your dependencies.
Sometimes, you need to build your assets or execute certain tasks when your deployment is finished. Via composer, you can automate these tasks through its scripts
On Clever Cloud, you have access to Node.js on PHP instances, so if you have grunt or gulp
(or any other task manager / scripts), you can create a custom script to install and execute your tasks.
Have a look at composer.json and build script to have an example.
You can login / register (with 20€ of free credits to test) on our Dashboard. Then, clone / fork this repo and create your own application.