add: 'Teaching Tech Together' by Greg Wilson (#11038)

books/free-programming-books-subjects.md

@@ -770,6 +770,7 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Professional Software Development For Students](https://mixmastamyk.bitbucket.io/pro_soft_dev/intro.html) - Mike G. Miller
 * [Software Engineering at Google](https://abseil.io/resources/swe-book) - Titus Winters, Tom Manshreck, Hyrum Wright
 * [Software Environment Concepts](https://softwareconcepts.vercel.app) - Amr Elmohamady *(:construction: in process)*
+* [Teaching Tech Together](http://teachtogether.tech/en/) - Greg Wilson (HTML)
 * [What I've Learned From Failure](https://leanpub.com/shippingsoftware/read) - Reginald Braithwaite