title: undefined method `assets' for #<Rails::Railtie::Configuration:0x000000056ac200>
body: <p>I am currently attempting to deploy my Rails 3.2.17 app to Heroku's cedar-14 stack.</p>
  
  <p>I am receiving an error running <code>git push heroku master</code>. Here is the relevant output:</p>
  
  <pre><code>remote:        Bundle completed (141.81s)
  remote:        Cleaning up the bundler cache.
  remote: -----&gt; Writing config/database.yml to read from DATABASE_URL
  remote:        Could not detect rake tasks
  remote:        ensure you can run `$ bundle exec rake -P` against your app with no environment variables present
  remote:        and using the production group of your Gemfile.
  remote:        rake aborted!
  remote:        NoMethodError: undefined method `assets' for #&lt;Rails::Railtie::Configuration:0x007f1e3f3dd998&gt;
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/railties-3.2.17/lib/rails/railtie/configuration.rb:85:in `method_missing'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/gritter-1.2.0/lib/gritter/railtie.rb:7:in `&lt;class:Railtie&gt;'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/gritter-1.2.0/lib/gritter/railtie.rb:3:in `&lt;module:Gritter&gt;'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/gritter-1.2.0/lib/gritter/railtie.rb:2:in `&lt;top (required)&gt;'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/activesupport-3.2.17/lib/active_support/dependencies.rb:251:in `require'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/activesupport-3.2.17/lib/active_support/dependencies.rb:251:in `block in require'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/activesupport-3.2.17/lib/active_support/dependencies.rb:236:in `load_dependency'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/activesupport-3.2.17/lib/active_support/dependencies.rb:251:in `require'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/gritter-1.2.0/lib/gritter.rb:26:in `&lt;top (required)&gt;'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/bundler-1.9.7/lib/bundler/runtime.rb:76:in `require'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/bundler-1.9.7/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/bundler-1.9.7/lib/bundler/runtime.rb:72:in `each'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/bundler-1.9.7/lib/bundler/runtime.rb:72:in `block in require'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/bundler-1.9.7/lib/bundler/runtime.rb:61:in `each'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/bundler-1.9.7/lib/bundler/runtime.rb:61:in `require'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/bundler-1.9.7/lib/bundler.rb:134:in `require'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/config/application.rb:13:in `&lt;top (required)&gt;'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/Rakefile:5:in `require'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/Rakefile:5:in `&lt;top (required)&gt;'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/lib/rake/rake_module.rb:28:in `load'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/lib/rake/rake_module.rb:28:in `load_rakefile'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:689:in `raw_load_rakefile'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:94:in `block in load_rakefile'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:176:in `standard_exception_handling'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:93:in `load_rakefile'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:77:in `block in run'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:176:in `standard_exception_handling'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:75:in `run'
  remote:        /tmp/build_9c69b395977c833063f1bf84ce228ae8/vendor/bundle/ruby/2.1.0/gems/rake-10.4.2/bin/rake:33:in `&lt;top (required)&gt;'
  remote:        vendor/bundle/bin/rake:16:in `load'
  remote:        vendor/bundle/bin/rake:16:in `&lt;main&gt;'
  remote: 
  remote: -----&gt; Discovering process types
  remote:        Procfile declares types -&gt; web
  remote:        Default types for Ruby  -&gt; console, rake, worker
  remote: 
  remote: -----&gt; Compressing... done, 58.6MB
  remote: -----&gt; Launching... done, v5
  remote:        https://alliance-billing-dev.herokuapp.com/ deployed to Heroku
  remote: 
  remote: Verifying deploy.... done.
  To https://git.heroku.com/alliance-billing-dev.git
   * [new branch]      master -&gt; master
  </code></pre>
  
  <p>Running <code>bundle exec rake -P</code> provides similar output. I have read several similar posts that relate to the assets method not being found, but all of these posts seem to concern gems that I am not using.</p>
  
  <p>My guess is that there is a compatibility issue with one of my gems and rails. Based on other posts, the gem in question always seems to be the gem preceding rails in the traceback. This would lead me to believe gritter-1.2.0 is the culprit. I do not, however, know how to proceed from there, or if my assumption is even correct.</p>
  
  <p>Here are the contents of my Gemfile, in case that can aid in finding a solution.</p>
  
  <pre><code>source 'https://rubygems.org'
  ruby '2.1.7'
  gem 'rails', '3.2.17'
  
  # Bundle edge Rails instead:
  # gem 'rails', :git =&gt; 'git://github.com/rails/rails.git'
  
  gem 'pg'
  gem 'sendgrid'
  gem 'newrelic_rpm'
  gem 'unicorn'
  gem 'money-rails'
  gem 'rack-timeout'
  # Gems used only for assets and not required
  # in production environments by default.
  group :assets do
    gem 'sass-rails',   '~&gt; 3.2.3'
    gem 'coffee-rails', '~&gt; 3.2.1'
    gem 'compass-rails'
  
    # See https://github.com/sstephenson/execjs#readme for more supported runtimes
    # gem 'therubyracer', :platforms =&gt; :ruby
  
    gem 'uglifier', '&gt;= 1.0.3'
  end
  
  
  gem 'activerecord-import'
  gem 'bootstrap-sass'
  gem 'cancan'
  gem 'carrierwave'
  gem 'chosen-rails'
  gem 'chronic'
  gem 'client_side_validations'
  gem 'client_side_validations-simple_form'
  gem 'date-input-rails'
  gem 'default_value_for', git: 'git://github.com/malagoli/default_value_for.git', ref: '3d458733a2'
  gem 'fog'
  gem 'gritter'
  gem 'haml'
  gem 'heroku'
  gem 'holidays', git: 'git://github.com/braintreeps/holidays.git'
  gem 'jquery-rails'
  gem 'kaminari'
  gem 'less-rails'
  gem 'paper_trail', '~&gt; 3.0.0'
  gem 'postgres-copy'
  gem 'prawn', '~&gt; 1.0.0rc2'
  gem 'quiet_assets', :group =&gt; :development
  gem 'rails-asset-jqueryui'
  gem 'ransack', git: 'git://github.com/ernie/ransack.git'
  gem 'simple_form'
  gem 'sorcery'
  gem 'strong_parameters'
  gem 'tabs_on_rails', git: 'git://github.com/xn/tabs_on_rails.git'
  gem 'therubyracer'
  gem 'twitter-bootstrap-rails'
  
  group :development do
    gem 'taps', :require =&gt; false # has an sqlite dependency, which heroku hates\
    gem 'sqlite3'
  end
  
  group :development, :test do
    #gem 'capybara'
    #gem 'cucumber-rails', :require =&gt; false
    gem 'annotate'
    gem 'factory_girl_rails'
    gem 'haml-rails'
    gem 'launchy'
    gem 'pry-rails'
    gem 'rspec-rails'
    gem 'shoulda', :require =&gt; false
  end
  
  group :test do
    #gem 'capybara-firebug', :require =&gt; false
    gem 'database_cleaner'
  end
  
  group :production do
    gem 'rails_12factor'
  end
  </code></pre>
  
  <p>Thank you in advance for any help.</p>