Retiring Sirona.

git-svn-id: https://svn.apache.org/repos/asf/incubator/sirona/trunk@1800941 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/RETIRED.txt b/RETIRED.txt
new file mode 100644
index 0000000..efc5759
--- /dev/null
+++ b/RETIRED.txt
@@ -0,0 +1,2 @@
+This podling has been retired, please see:
+http://incubator.apache.org/projects/index.html#sirona