"app error: Missing `secret_token` and `secret_key_base` for 'production' environment"

Using the 1-Click Ruby on Rails on Ubuntu 14.04 Image, I’m getting the following error on initial request to the app:

ERROR: app error: Missing `secret_token` and `secret_key_base` for 'production' environment, set these values in `config/secrets.yml` (RuntimeError)

my config/secrets.yml file includes the following:

# Do not keep production secrets in the repository,
# instead read values from the environment.
production:
  secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>
  secret_token: <%= ENV["SECRET_KEY_BASE"] %>

and I’ve set ENV["SECRET_KEY_BASE"]

stack: ‘rails’, ‘4.2.0’ ruby ‘2.1.3’ unicorn (4.8.3)

all my reading says that secret_token is no longer used in Rails 4.2.