406 error when adding starter code

Greetings All:

So, I just set up student repo invites for a classroom repos, and afterward went back in to “edit assignment”… When I selected the option to “Add starter code” and pointed it to a public repo containing a .gitignore file and a readme.md, I got this error. I have now tried 3x, with the same result:

Request not acceptable
The requested resource is unavailable in the format requested.
Go back to classroom dashboard

Any ideas?

ah-ha! Resolved! Just had to flag the code-containing repo as a template repo.