1. Added gems for production:
+  gem 'rails_12factor'
+  gem 'unicorn'

2.  Changed to Ruby 2.0 and tested (I had ruby 2.1.2 installed before
    Heroku wants ruby 2.0.0
+ruby '2.0.0'

3. Made changes requested by Heroku by adding a line in the config/application file
-- diff --git a/config/application.rb b/config/application.rb
+    # Heroku says initialize_on_precompile: https://devcenter.heroku.com/articles/getting-started-with-rails3#prerequisites
+    config.assets.initialize_on_precompile = false

4. Installed unicorn server for production.
-- Backed my unicorn config file out of initializers.
Add the config/unicorn.rp file