Heroku can't find out that python is necessary - django

Question

I have a project with the structure similar to what is described in Two Scoops of Django.
Namely:
1. photoarchive_project is repository root (where .git lives).
2. The project itself is photoarchive.
3. Config files are separate for separate realities.
The traceback and other info is below.
The file runtime.txt is situated next to .git directory. That is in the very directory where git is initialized.
The problem is: it can't even determine that python should be applied. Could you give me a kick here?
.git/config
[core]
repositoryformatversion = 0
filemode = true
bare = false
logallrefupdates = true
[remote "origin"]
url = ssh://git#bitbucket.org/Kifsif/photoarchive.git
fetch = +refs/heads/*:refs/remotes/origin/*
[branch "master"]
remote = origin
merge = refs/heads/master
[remote "heroku"]
url = https://git.heroku.com/powerful-plains-97572.git
fetch = +refs/heads/*:refs/remotes/heroku/*
traceback
(photoarchive) michael#ThinkPad:~/workspace/photoarchive_project$ git push
heroku master
Counting objects: 3909, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (3617/3617), done.
Writing objects: 100% (3909/3909), 686.44 KiB | 0 bytes/s, done.
Total 3909 (delta 2260), reused 0 (delta 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 powerful-plains-97572.
remote:
To https://git.heroku.com/powerful-plains-97572.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/powerful-plains-97572.git'
tree
(photoarchive) michael#ThinkPad:~/workspace/photoarchive_project$ tree
.
├── docs
├── media
├── photoarchive
│   ├── config
│   │   ├── settings
│   │   │   ├── base.py
│   │   │   ├── constants.py
│   │   │   ├── heroku.py
│   │   │   ├── __init__.py
│   │   │   ├── local.py
│   │   │   └── production.py
│   └── manage.py
├── .git
├── .gitignore
├── Procfile
└── runtime.txt
runtime.txt
python-3.6.1
I

Answer 1

You need to define a requirements.txt inside the root of your project folder. This file should contain a list of all your project dependencies.
You can generate this file on your local development machine by running:
$ pip freeze > requirements.txt
Then checking it into version control, and pushing it to Heroku.
Heroku looks for this file to determine that your app is, in fact, a Python application =)