Add travis build status

Readme.md

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 ## Hacker Slides
 
+[![Build Status](https://travis-ci.org/msoedov/hacker-slides.svg?branch=master)](https://travis-ci.org/msoedov/hacker-slides)
+
 This repo is a reworked version of [Sandstorm Hacker Slides](https://github.com/jacksingleton/hacker-slides) which features easy set up run outside of Sandstorm and without vagrant-spk. Likewise you can publish and edit your previous markdown slides which is not supported in the original version.
 
 | Edit mode | Published  |