Resolve "Learning materials"

Review here

Closes #276 (closed) #236 (closed)

_includes/header.html

@@ -92,6 +92,7 @@ See also:
                             <p><a href="{{ "documentation" | relative_url }}">&nbsp;&nbsp;<i>Documentation</i></a></p>
                             <p><a href="{{ "reports" | relative_url }}">&nbsp;&nbsp;<i>Reports</i></a></p>
                             <p><a href="{{ "services/overall/survey" | relative_url }}">&nbsp;&nbsp;<i>Surveys</i></a></p>
+                            <p><a href="{{ "events" | relative_url }}">&nbsp;&nbsp;<i>Events Archive</i></a></p>
                         </div>
                     </details>