Dnode -node.js

 refer    http://getcomposer.org/doc/00-intro.md

Let's say you are creating a project, and you need a library that does logging. You decide to use monolog. In order to add it to your project, all you need to do is create a composer.json file which describes the project's dependencies.

{
    "require": {
        "monolog/monolog": "1.0.*"
    }
}

We are simply stating that our project requires some monolog/monolog package, any version beginning with 1.0.

$ sudo wget http://getcomposer.org/composer.phar 
$ sudo php composer.phar install 

check for curl if not then

sudo apt-get install php5-curl

sudo service php5-fpm restart