Update build badge to Travis

Author: reinink

README.md

@@ -4,7 +4,7 @@
 </p>
 
 <p align="center">
-    <a href="https://app.codeship.com/projects/254859"><img src="https://img.shields.io/codeship/cdd4ad20-a319-0135-c87c-02251d502cd2.svg" alt="Codeship Status"></a>
+    <a href="https://travis-ci.org/tailwindcss/tailwindcss"><img src="https://img.shields.io/travis/tailwindcss/tailwindcss/master.svg" alt="Build Status"></a>
     <a href="https://www.npmjs.com/package/tailwindcss"><img src="https://img.shields.io/npm/dt/tailwindcss.svg" alt="Total Downloads"></a>
     <a href="https://github.com/tailwindcss/tailwindcss/releases"><img src="https://img.shields.io/npm/v/tailwindcss.svg" alt="Latest Release"></a>
     <a href="https://github.com/tailwindcss/tailwindcss/blob/master/LICENSE"><img src="https://img.shields.io/npm/l/tailwindcss.svg" alt="License"></a>