Add "sonarcloud" badge.
diff --git a/README.md b/README.md
index bff4484..51f9005 100644
--- a/README.md
+++ b/README.md
@@ -45,6 +45,7 @@
[](https://travis-ci.org/apache/commons-numbers)
[](https://coveralls.io/r/apache/commons-numbers)
+[](https://sonarcloud.io/dashboard?id=commons-numbers)
[](https://maven-badges.herokuapp.com/maven-central/org.apache.commons/commons-numbers-parent/)
The Apache Commons Numbers project provides number types and utilities.