Error loading project on heroku. What's wrong?

Question

Django

added files
Procfile
web: gunicorn myfist.wsgi --log-file -
runtime.txt .gitignore
python-3.7.6

__pycache__/
*pyc
db.sqlite3

requirements.txt

dj-database-url==0.5.0
Django==3.0.3
djangorestframework==3.11.0
gunicorn==20.0.4
oauthlib==3.1.0
PyJWT==1.7.1
requests==2.23.0
requests-oauthlib==1.3.0
six==1.14.0
whitenoise==5.2.0
wrapt==1.12.0
psycopg2==2.6.2

I commented out my project and submitted by
git push heroku master
But I get an error

Enumerating objects: 45, done.
Counting objects: 100% (45/45), done.
Delta compression using up to 8 threads
Compressing objects: 100% (37/37), done.
Writing objects: 100% (45/45), 13.70 KiB | 425.00 KiB/s, done.
Total 45 (delta 6), reused 3 (delta 0), pack-reused 0
remote: Compressing source files... done.
remote: Building source:
remote:
remote: ! No default language could be detected for this app.
remote: HINT: This occurs when Heroku cannot detect the buildpack to use for this application automatically.
remote: See https://devcenter.heroku.com/articles/buildpacks
remote:
remote: ! Push failed
remote: Verifying deploy...
remote:
remote: ! Push rejected to shielded-bastion-00322.
remote:
To https://git.heroku.com/shielded-bastion-00322.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to ' https://git.heroku.com/shielded-bastion-00322.git '

What have I done wrong?

After selecting the language manually

Enumerating objects: 50, done.
Counting objects: 100% (50/50), done.
Delta compression using up to 8 threads
Compressing objects: 100% (42/42), done.
Writing objects: 100% (50/50), 14.01 KiB | 421.00 KiB/s, done.
Total 50 (delta 10), reused 3 (delta 0), pack-reused 0
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> App not compatible with buildpack: https://buildpack-registry.s3.amazonaws.com/buildp...
remote: More info: https://devcenter. heroku.com/articles/buildpacks#d...
remote:
remote: ! Push failed
remote: Verifying deploy...
remote:
remote: ! Push rejected to shielded-bastion-00322.
remote:
To https://git.heroku.com/shielded-bastion-00322.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to ' https://git.heroku.com/shielded-bastion-00322.git '

Answer 1

Heroku was unable to determine the language your project is using. To do this manually, go from the dashboard of the project to the Settings section, in the Buildpacks item, click Add buildpack and select python