Heroku and LetsEncrypt

I have my site www.foo.bar hosted on Heroku successfully, but now I want to add ssl cert to my site using LetsEncrypt. In order to successfully do this, I need to generate a directory www.foo.bar/.well-known/acme-challenge/(insert random string here) that displays a that random code.

I followed this post. It did nothing for me. I could not get the .well-known route to work. I could only see “not found” when I navigated to that page.

In addition, I tried moving the /.well-known directory to the project root and added both:
include: ['.well-known/acme-challenge'] keep_files: ['.well-known/acme-challenge']
to my _config.yml file.

Anyone else have suggestions or successfully done this?

Try:
include: [".well-known",".well-known/file"]
I have tested on my end and it is working. The difference here is listed the folder and the asset both are unique items.