The problems started when you run the command git push heroku master got error
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to send some links "https://git.heroku.com/modernarchetype.git"
On the advice of SO created a new branch, called "tempbranch". It worked.
Counting objects: 6395 ready.
Delta compression using up to 4 threads.
Compressing objects: 100% (5328/5328) ready.
Write objects: 100% (6395/6395), 8.84 MiB | 57.00 KiB/s, done.
Total 6395 (delta 1885), reused 0 (delta 0)
remote: Pushed to non-master branch, skipping build.
* [new branch] tempbranch -> tempbranch
Next, run the command heroku run python manage.py migrate and get the error:
Running python manage.py migrate on ⬢ modernarchetype... !
▸ Cannot run a one-off process at this time. Please try again later.
Help to solve, first time working with Heroku, and Django not long study.