Github specification:
https://help.github.com/articles/creating-a-footer/

- the footer is rendered below the wiki page content.
- a direct link to edit the footer.

And use getWikiPage to avoid code repetition.

A simple wiki page (markdown file "_Sidebar.md") is used as a sidebar menu for the wiki.

Github specification:
https://help.github.com/articles/creating-a-sidebar/

- the sidebar is rendered below the pages index.
- if you click on page index "counter" you can collapse or expand the
  page list.