update repo and install composer

$ sudo apt-get update
$ sudo apt-get install curl php5-cli git
$ curl -sS https://getcomposer.org/installer | sudo php — –install-dir=/usr/local/bin –filename=composer

test it

$ composer

update

$ cd /usr/share/nginx/html/kamp/
$ composer update

if you see the following error
PHP Fatal error: Uncaught exception ‘ErrorException’ with message ‘proc_open(): fork failed – Cannot allocate memory’ in phar

$ sudo /bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
$ sudo /sbin/mkswap /var/swap.1
$ sudo /sbin/swapon /var/swap.1

update

$ composer update