Nitrous.io and Heroku

I've been following the tutorial at http://ruby.railstutorial.org/ruby-on-rails-tutorial-book. I started through the tutorial the first time using Cloud 9 IDE, but then switched over to nitrous.io when Rails 4.0 and Ruby 2.0 were released. Although the tutorial states that using Ruby 1.9.3 is fine, I just felt more comfortable using the newer version of Ruby, and it was easier to start using Ruby 2.0 in nitrous than in c9. The terminal in nitrous.io also feels faster.

In any event, the tutorial is great and I was breezing through it until I got to the step where I needed to push to Heroku. I kept running into the error:

Permission denied (publickey).

I spun my wheels for a bit following the instructions nitrous.io instructions on how to connect nitrous with github. But didn't find the answer until I paid better attention to the Heroku help page. Obviously (in hindsight), if I get a publickey issue when pushing to Heroku, I should look at that help page instead of connecting to github.

In any event, if you get a publickey error pushing to Heroku from nitrous.io, I got it to work by running the following command in the terminal:

$ heroku keys:add