title: Why do I get 'uninitialized constant' in Active Admin when I create a new resource
body: <p>I have set up Rails active admin and the interface loads up just fine for me here is my setup in my Gemfile:</p>
  
  <pre><code># Use all the things Active Admin needs ================== 
  gem 'devise',              github: 'plataformatec/devise'
  gem 'responders',          github: 'plataformatec/responders'
  gem 'inherited_resources', github: 'josevalim/inherited_resources'
  gem 'ransack',             github: 'ernie/ransack'
  gem 'activeadmin',         github: 'gregbell/active_admin', branch: 'rails4'
  gem 'formtastic',          github: 'justinfrench/formtastic'
  
  gem "friendly_id", "~&gt; 5.0.2"
  </code></pre>
  
  <p>I can go to /admin and it loads up the interface just fine.</p>
  
  <p>The only issue I have is when I say do command:</p>
  
  <pre><code>rails generate active_admin:resource Pages
  </code></pre>
  
  <p>It generates the resource in my /app/admin/pages.rb but when I reload the page I get the error.</p>
  
  <p><strong>The complete error message:</strong></p>
  
  <pre><code>NameError
  uninitialized constant Pages
  
  Extracted source (around line #1):
  1 ActiveAdmin.register Pages do
  2
  3 end
  
  Rails.root: /Freelance/Current Projects/Birch/forge
  
  Application Trace | Framework Trace | Full Trace
  app/admin/pages.rb:1:in `&lt;top (required)&gt;'
  config/routes.rb:2:in `block in &lt;top (required)&gt;'
  config/routes.rb:1:in `&lt;top (required)&gt;'
  This error occurred while loading the following files:
     /Freelance/Current Projects/Birch/forge/config/routes.rb
     /Freelance/Current Projects/Birch/forge/app/admin/pages.rb
  </code></pre>
  
  <p>Has anyone got a clue as to why that would happen? I have done nothing to break it or anything so not sure what it could be.</p>