Add doozer build badge (#956)

README.md

@@ -5,7 +5,8 @@ Copyright (c) 2012-2016, [Magnus Edenhill](http://www.edenhill.se/).
 
 [https://github.com/edenhill/librdkafka](https://github.com/edenhill/librdkafka)
 
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+
 
 **librdkafka** is a C library implementation of the
 [Apache Kafka](http://kafka.apache.org/) protocol, containing both