title: yii2 installation via composer - Could not open input file: composer.phar
body: <p>I am trying to install the <code>yii2</code> and after I installed the composer I tried to run <code>composer.phar</code> <code>global require "fxp/composer-asset-plugin:~1.1.1"</code>
  it says : </p>
  
  <blockquote>
    <p>Could not open input file: composer.phar</p>
  </blockquote>
  
  <p>Any suggestions ?</p>