Heroku is a cloud platform as a service (PaaS) supporting several programming languages. Anything related to managing such applications should be tagged with this. This including but not limited to things like dyno management, a setting up ssl and managing addons.
In this post, the author suggest a way to get SSL on Heroku without paying Heroku for it:
Pay Cloudflare for premium service, and get SSL support with it.
Create a CNAME in cloudflare that points to ...