title: NameError on executing 'rails s'
body: <p>I started this tutorial for Rails. I just created the app and was going to test the default welcome page and this happened:</p>
  
  <pre><code>D:\Programming\Rails Projects\simpleCMS&gt;rails server
      C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.3/lib/action_view/helpers.rb:40:in `&lt;module:Helpers&gt;': uninitialized constant ActionView::Helpers::ActiveModelHelper (NameError)
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.3/lib/action_view/helpers.rb:4:in `&lt;module:ActionView&gt;'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.3/lib/action_view/helpers.rb:3:in `&lt;top (required)&gt;'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.3/lib/action_view/base.rb:5:in `require'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.3/lib/action_view/base.rb:5:in `&lt;top (required)&gt;'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/web-console-2.2.1/lib/web_console/template.rb:7:in `&lt;class:Template&gt;'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/web-console-2.2.1/lib/web_console/template.rb:6:in `&lt;module:WebConsole&gt;'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/web-console-2.2.1/lib/web_console/template.rb:1:in `&lt;top (required)&gt;'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/web-console-2.2.1/lib/web_console.rb:12:in `require'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/web-console-2.2.1/lib/web_console.rb:12:in `&lt;top (required)&gt;'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/web-console-2.2.1/lib/web-console.rb:1:in `require'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/web-console-2.2.1/lib/web-console.rb:1:in `&lt;top (required)&gt;'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:76:in `require'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:72:in `each'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:72:in `block in require'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:61:in `each'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:61:in `require'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.10.6/lib/bundler.rb:134:in `require'
              from D:/Programming/Rails Projects/simpleCMS/config/application.rb:7:in `&lt;top (required)&gt;'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:78:in `require'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:78:in `block in server'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:75:in `tap'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:75:in `server'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
              from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.3/lib/rails/commands.rb:17:in `&lt;top (required)&gt;'
              from bin/rails:4:in `require'
              from bin/rails:4:in `&lt;main&gt;'
  </code></pre>
  
  <p>My gemfile (without the comments):</p>
  
  <pre><code>source 'https://rubygems.org'
  gem 'rails', '4.2.3'
  gem 'mysql2'
  gem 'jbuilder', '~&gt; 2.0'
  gem 'sdoc', '~&gt; 0.4.0', group: :doc
  group :development, :test do
      gem 'byebug'
      gem 'web-console', '~&gt; 2.0'
  end
  gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
  </code></pre>