title: Ember 1.0.0: Ember.State has been moved into a plugin: https://github.com/emberjs/ember-states
body: <p>I am migrating an Ember rc7 project to Ember 1.0.0.  I have this unusual error: </p>
  
  <pre><code>Ember.State has been moved into a plugin: https://github.com/emberjs/ember-states
  </code></pre>
  
  <p>I have the error only if I use a combination of Ember.js 1.0.0 in combination with Ember data 0.13.  If I include the extra ember-states lib, then everything works fine.</p>
  
  <p>What is the reason of this change ?  Why do I need an additional lib ?</p>
  
  <p>If I use Ember.js 1.0.0 in combination with Ember data 1.0.0 beta.1, then this error does not occur.</p>
  
  <p>I hope somebody can explain why this additional lib seems to be needed in some cases ?</p>
  
  <p>Marc</p>