Add author to example

Change-Id: I32ce8492832c240afcc119790b96b127dc92d413
diff --git a/examples/ids.Rmd b/examples/ids.Rmd
index 81adb21..f9693ce 100644
--- a/examples/ids.Rmd
+++ b/examples/ids.Rmd
@@ -1,7 +1,9 @@
 ---
 title: "IDS theme for revealjs"
 subtitle: "a demo"
-author: Marc Kupietz
+author:
+  - name: Marc Kupietz
+  - name: John Doe
 institute: "IDS Mannheim"
 date: "`r paste0('Mannheim, ', Sys.Date())`"
 output: