Add build status icon

Philippus · Philippus · commit d59993b597fb · 2019-02-15T20:36:57.000+01:00
diff --git a/README.md b/README.md
@@ -1,4 +1,4 @@
-# scala-async [<img src="https://img.shields.io/maven-central/v/org.scala-lang.modules/scala-async_2.12.svg?label=latest%20release%20for%202.12">](http://search.maven.org/#search%7Cga%7C1%7Cg%3Aorg.scala-lang.modules%20a%3Ascala-async_2.12)
+# scala-async [![Build Status](https://travis-ci.org/scala/scala-async.svg?branch=master)](https://travis-ci.org/scala/scala-async) [<img src="https://img.shields.io/maven-central/v/org.scala-lang.modules/scala-async_2.12.svg?label=latest%20release%20for%202.12">](http://search.maven.org/#search%7Cga%7C1%7Cg%3Aorg.scala-lang.modules%20a%3Ascala-async_2.12)
 
 ## Supported Scala versions
 

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-# scala-async [<img src="https://img.shields.io/maven-central/v/org.scala-lang.modules/scala-async_2.12.svg?label=latest%20release%20for%202.12">](http://search.maven.org/#search%7Cga%7C1%7Cg%3Aorg.scala-lang.modules%20a%3Ascala-async_2.12)`
	`1`	`+# scala-async [![Build Status](https://travis-ci.org/scala/scala-async.svg?branch=master)](https://travis-ci.org/scala/scala-async) [<img src="https://img.shields.io/maven-central/v/org.scala-lang.modules/scala-async_2.12.svg?label=latest%20release%20for%202.12">](http://search.maven.org/#search%7Cga%7C1%7Cg%3Aorg.scala-lang.modules%20a%3Ascala-async_2.12)`
`2`	`2`
`3`	`3`	`## Supported Scala versions`
`4`	`4`