title: Devise::TestHelpers docs unclear on Devise.mappings[:mapping] usage
body: <p>In the docs for using the Devise TestHelpers it states to use lines such as...</p>
  
  <pre><code>@request.env["devise.mapping"] = Devise.mappings[:admin]
  </code></pre>
  
  <p>or</p>
  
  <pre><code>@request.env["devise.mapping"] = Devise.mappings[:user]
  </code></pre>
  
  <p>...to let Devise know which resource or mapping to use since the controller tests bypass routes.rb. I am not clear on what these mappings are. I have not set up anything special in this regard, and I do not have a specific mapping in mind. I have User, Admin, Refinery, and Superuser roles, a la Rolify, and I am using Cancan for its abilities.</p>
  
  <p>Can you clarify? ...perhaps the resource name is what us meant?</p>
  
  <p>TIA.
  -Matt</p>