Mostlycurious.com is a static Jekyll site hosted on Github. This has been pretty convenient compared to my prior efforts, which have included Posterous, Tumblr, Ghost. One thing I have always wanted to include was a site-specific search bar.
This is not a new problem, and a quick search led me to a previously answered Stackoverflow post. I decided to try Google custom search, because it seems pretty easy for a first attempt (see below).
On the web there is another good example and walkthrough from Gleb Bahmutov.