Added travis badge

Author: vtsykun

README.md

@@ -2,7 +2,7 @@
 
 Symfony [Datadog][1] integration to monitor and track for application errors and send notifications about them.
 
-[![Latest Stable Version](https://poser.pugx.org/okvpn/datadog-symfony/v/stable)](https://packagist.org/packages/okvpn/datadog-symfony) [![Latest Unstable Version](https://poser.pugx.org/okvpn/datadog-symfony/v/unstable)](https://packagist.org/packages/okvpn/datadog-symfony) [![Total Downloads](https://poser.pugx.org/okvpn/datadog-symfony/downloads)](https://packagist.org/packages/okvpn/datadog-symfony) [![License](https://poser.pugx.org/okvpn/datadog-symfony/license)](https://packagist.org/packages/okvpn/datadog-symfony)
+[![Build Status](https://travis-ci.org/okvpn/datadog-symfony.svg?branch=master)](https://travis-ci.org/okvpn/datadog-symfony) [![Latest Stable Version](https://poser.pugx.org/okvpn/datadog-symfony/v/stable)](https://packagist.org/packages/okvpn/datadog-symfony) [![Latest Unstable Version](https://poser.pugx.org/okvpn/datadog-symfony/v/unstable)](https://packagist.org/packages/okvpn/datadog-symfony) [![Total Downloads](https://poser.pugx.org/okvpn/datadog-symfony/downloads)](https://packagist.org/packages/okvpn/datadog-symfony) [![License](https://poser.pugx.org/okvpn/datadog-symfony/license)](https://packagist.org/packages/okvpn/datadog-symfony)
 
 ## Benefits