Rails with Yummly Gem works fine locally, but fails on Heroku - ruby-on-rails

Question

I am a novice to Ruby on Rails and am following Michael Hartl's 3.2 tutorial book as a reference. I got my app running and deployed onto Heroku fine until I try to add the unofficial yummly gem.
http://rubygems.org/gems/yummly/versions/0.0.7
I get it to work locally (makes and fetches the api fine), but when I push it to Heroku, the app crashes and says it can't find Yummly.rb in the helper files on line 5.
Other than including
require Yummly
in my controller class and
gem "yummly"
(and running bundle install) in my Gemfile, what could I be missing? Perhaps I need to specify that the gem needs to be the latest version 0.0.9 (I couldn't get it to install so I didn't try to change it)?
Does this have to do with Heroku specifically? or does it have to do with the Yummly Gem specifically?
Heroku logs as follows
State changed from crashed to starting
Starting process with command `bundle exec thin start -R config.ru -e $RAILS_ENV -p 51790`
DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /app/config/environment.rb:5)
DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /app/config/environment.rb:5)
/app/vendor/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:317:in `rescue in depend_on': Missing helper file helpers/Yummly.rb (LoadError)
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/action_controller/metal/helpers.rb:92:in `modules_for_helpers'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/abstract_controller/helpers.rb:131:in `modules_for_helpers'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/abstract_controller/helpers.rb:131:in `map!'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/abstract_controller/helpers.rb:135:in `block in modules_for_helpers'
from /app/vendor/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:312:in `depend_on'
from /app/vendor/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:225:in `require_dependency'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/abstract_controller/helpers.rb:159:in `default_helper_module!'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/action_controller/metal/params_wrapper.rb:135:in `inherited'
from /app/app/controllers/application_controller.rb:1:in `<top (required)>'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/abstract_controller/helpers.rb:95:in `helper'
from /app/vendor/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
from /app/vendor/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `block in require'
from /app/vendor/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/engine.rb:439:in `block (2 levels) in eager_load!'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/abstract_controller/railties/routes_helpers.rb:7:in `block (2 levels) in with'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/action_controller/railties/paths.rb:7:in `block (2 levels) in with'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/abstract_controller/helpers.rb:22:in `block in inherited'
rom /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/abstract_controller/helpers.rb:22:in `class_eval'
from /app/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/abstract_controller/helpers.rb:22:in `inherited'
from /app/vendor/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/engine.rb:436:in `ea

Answer 1

require takes a file or gem name to require so the classes and modules it defines are accessible in the current file.
Therefore, you should do the following :
require 'yummly'
Note the fact that it's a string and not a constant.
It is also completely downcased, as per convention, filenames in ruby never takes any uppercase.
However, since you're using bundler, you should know that is manages requiring your dependencies automatically. Therefore, you don't need to require your dependency at all.