Add build status.

davidmorgan · web-flow · commit 4781829860fe · 2016-06-19T18:13:20.000+02:00
diff --git a/README.md b/README.md
@@ -1,5 +1,5 @@
 # Built JSON for Dart
-
+[![Build Status](https://travis-ci.org/google/built_json.dart.svg?branch=master)](https://travis-ci.org/google/built_json.dart)
 ## Introduction
 
 Built JSON provides serialization for the [Libraries for Object Oriented Dart]
