Add command to generate the docs site

docs/modules/ROOT/partials/building.adoc

@@ -42,6 +42,13 @@ parsing or rendering it, just copying it to `${main.basedir}`
 any changes in the README it will then show up after a Maven build as
 a modified file in the correct place. Just commit it and push the change.
 
+You can generate the docs site using the following command:
+
+[indent=0]
+----
+	./mvnw -pl docs -P docs antora:antora
+----
+
 [[working-with-the-code]]
 == Working with the code
 If you don't have an IDE preference we would recommend that you use