Doc fauxinnati

It is so cool and thus worth a paragraph in our docs for it.

Then it will be our responsibility to maintain the tool since it
is public which should not increase any security risks because
the tool is accessible by anyone already.

Author: hongkailiu

docs/dev/feed-cvo-custom-graphs.md

@@ -28,6 +28,8 @@ Example:
 }
 ```
 
+More examples can be found at [fauxinnati](https://fauxinnati-fauxinnati.apps.ota-stage.q2z4.p1.openshiftapps.com/). See [a demo](https://asciinema.org/a/hUwpV4pyhGK0k0nI68KzAO3pv) to use it as `cv.spec.upstream`. It currently does not inject real payload URLs, and thus we cannot do a cluster upgrade with it. We may modify the returned graph and host it somewhere (see the example in this page) to achieve it.
+
 ### Step-2
 
 Host the file in any location where the cluster version operator can access it.