composer global

fortrabbit.yml

pre: pre-deploy.php
sustained:
    - vendor
    - .composer-global

pre-deploy.php

<?php

$appName    = getenv('APP_NAME');
$installDir = "/srv/app/$appName/htdocs/.composer-global";
$package    = "fxp/composer-asset-plugin";

if (!is_dir($installDir)) {
  mkdir($installDir);	
}

if (!is_dir("$installDir/vendor")) {
  exec("composer global require -d $installDir $package");
}