Ask HN: Who here has started a book (and launched?) with no list/etc

I am thinking about and starting the early stages of a book/course to build a SaaS app in the latest version of Ruby on Rails. Specifically, I have battle tested an approach and skeleton for the various parts of a SaaS application in RoR.

With that being said, I don’t have a deep list of subscribers and was wondering if anyone here had experience building that from scratch, what tools they used to collect signup or presales and tools they used to build their assets.

PS - Let me know if you are interested and I can post some links to my (for the time being) GumRoad pre-sale pages.