Fix missing shortcode in doc

Use new syntax for example.
Correct alias
showcase: update ucsb entry
Fixed typo in summaries description in the documentation
Github page strategy for username.github.io repos

The whole article should maybe be rewriten to have a better content flow (maybe adding a table of content), to introduce both possible strategies. But at least, the technical steps are there!
Add Ace template engine support
Triggering EDITOR after hugo new.