Add content to groovy-reports.md

docs/groovy-reports.md

@@ -4,4 +4,16 @@ Groovy reports are just Groovy code that generates html.
 You are completely free to generate that html any way you prefer.
 
 A convenient way it to use the Html class of the gmd library which has some 
-nice ways of dealing with
+nice ways of dealing with Matrix tables and charts.
+
+If you want to add bootstrap and highlightjs to your html, you can use the
+se.alipsa.groovy.gmd.HtmlDecorator.decorate() method to do that e.g:
+
+```groovy
+import se.alipsa.groovy.gmd.*
+
+Html html = new Html()
+html.add("<h1>Hello</h1>")
+HtmlDecorator.decorate(html.toString())
+
+```