Composer installation

Install composer globally. See https://getcomposer.org/doc/00-intro.md#installation-linux-unix-osx

cd /usr/local/src/
curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer

If you are behind a firewall and composer is not responding, add the following lines to composer.json (see: http://codinginharmony.blogspot.de/2012/10/forcing-composer-to-use-https.html)

"repositories": [
   {
        "type": "composer", 
        "url": "https://packagist.org"
   },
   { "packagist": false }
]