To keep secrets confidential, we're using environment variables set in Heroku. You'll see stuff like this in the codebase:
config.secret_key_base = ENV['SECRET_KEY_BASE']
That means if you just run rails or rspec you might get something like this, (maybe only after you try to request a page):
$ rails s
...
DEPRECATION WARNING: You didn't set config.secret_key_base. Read the upgrade documentation to learn more about this new config option.
...
So, we're using Foreman to take care of the heavy lifting for us. First, you'll have to put the following in a file called .env:
SECRET_KEY_BASE=fake_secret_key_base
Make sure that fake_secret_key_base is in quotes. (You can use the key generated in the error message above for the fake keys if you'd like, or rake secret.) .env is ignored in .gitignore, so don't expect it to be under source control.
When you want to run something like rails or rspec, prepend it with foreman run bundle exec. To make my life easier, I have the following aliases in my .bashrc file:
alias fr="foreman run bundle exec rails"
alias fs="foreman run bundle exec rspec"
Because these are also needed for precompiling assets, I've enabled Heroku's user-env-compile.
For more information on using environment variables on Heroku, check out Heroku's article on Configuration and Config Vars.