Heroku push rejected, no Cedar-supported app detected

Question

I'm creating a Rails app with Rails 3.1.3:

git init
git remote add heroku <my heroku repo>
git add .
git commit -a -m "First commit"
git push heroku master

Got:

Counting objects: 102, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (86/86), done.
Writing objects: 100% (102/102), 315.47 KiB, done.
Total 102 (delta 3), reused 0 (delta 0)

**-----> Heroku receiving push
 !     Heroku push rejected, no Cedar-supported app detected**

To [email protected]:electric-dusk-3217.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to <my heroku rep>

Answer 1

I had a similar problem, but with Django (incorrectly named "requirements.txt"). I think to generalize the other answers here, when you get this error it's because Heroku is missing some key file that it uses to identify your app (and its type).

• php: index.php
• python: requirements.txt
• ruby: Gemfile # note the capitalization
• node: package.json

Answer 2

The problem was that my "Gemfile" was named "gemfile"

Answer 3

I ran into this error message, but my problem was that my rails app was not in the root directory of my git repo. After I moved the files into the root dir, everything worked.