Add reference to Ecosystem CI in extension authors doc

docs/src/main/asciidoc/writing-extensions.adoc

@@ -2824,3 +2824,10 @@ Then, at the end of your documentation, include the extensive documentation:
 ----
 
 Finally, generate the documentation and check it out.
+
+== Continuous testing of your extension
+
+In order to make it easy for extension authors to test their extensions daily against the latest snapshot of Quarkus, Quarkus has introduced
+the notion of the Ecosystem CI. The Ecosystem CI link:https://github.com/quarkusio/quarkus-ecosystem-ci/blob/master/README.adoc[README]
+has all the details on how to set up a Github Actions job to take advantage of this capability, while this link:https://www.youtube.com/watch?v=VpbRA1n0hHQ[video] provides an overview
+of what the process looks like.