title: Undefined method `tagged' for Formatter error after Rails 4 upgrade
body: <p>I have upgraded from Rails 3.2 to Rails 4 by following the Ruby Screencast guide. My tests are running and the server starts, yet I receive an error when I send a request:</p>
  
  <pre><code>ERROR NoMethodError: undefined method `tagged' for #&lt;Formatter:0x000000057f5dc8&gt;
  
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-4.0.0/lib/active_support/tagged_logging.rb:67:in `tagged'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/railties-4.0.0/lib/rails/rack/logger.rb:21:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/quiet_assets-1.0.2/lib/quiet_assets.rb:18:in `call_with_quiet_assets'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/actionpack-4.0.0/lib/action_dispatch/middleware/request_id.rb:21:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.5.2/lib/rack/methodoverride.rb:21:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.5.2/lib/rack/runtime.rb:17:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-4.0.0/lib/active_support/cache/strategy/local_cache.rb:83:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/actionpack-4.0.0/lib/action_dispatch/middleware/static.rb:64:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/railties-4.0.0/lib/rails/engine.rb:511:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/railties-4.0.0/lib/rails/application.rb:97:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.5.2/lib/rack/lock.rb:17:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.5.2/lib/rack/content_length.rb:14:in `call'
  /home/mahoni/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.5.2/lib/rack/handler/webrick.rb:60:in `service'
  /home/mahoni/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
  /home/mahoni/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
  /home/mahoni/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'
  </code></pre>
  
  <p>I have I have looked at the code, and it does not make sense for me. It calls <code>logger.tagged</code>. The object behind the variable <code>logger</code> is not a logger, but a <code>Formatter</code> object. This is strange.</p>
  
  <p>Any idea what could cause this? So far I:</p>
  
  <ul>
  <li>deleted my <code>Gemfile.lock</code></li>
  <li><code>gem update rails</code></li>
  <li><code>bundle install</code></li>
  <li><code>bundle update</code></li>
  </ul>
  
  <p>In this and different orders. How can I approach this?</p>