update example to use newer ruby image
@@ -242,7 +242,7 @@ You can start using `s2i` right away (see [releases](https://github.com/openshif
with the following test sources and publicly available images:
```
-$ s2i build https://github.com/openshift/ruby-hello-world centos/ruby-23-centos7 test-ruby-app
+$ s2i build https://github.com/openshift/ruby-hello-world centos/ruby-25-centos7 test-ruby-app
$ docker run --rm -i -p :8080 -t test-ruby-app
```
