title: +entityForName: could not locate an entity named 'Dogs' in this model.
body: <p>A little question regarding Core data models.</p>
  
  <p>Here is why I'm posting : <code>+entityForName: could not locate an entity named 'Dogs' in this model.</code></p>
  
  <p>What I wanna do :
  I wanna create an app that will read/write in core data details about animals with 2 entities <code>Cats</code> and <code>Dogs</code>.</p>
  
  <p>-For that I create a window-based project with "use core data" checked.
  -Then I create my views, and click on "animals.xcdatamodeld" file to create a first entity called <code>Cats</code>. I add the attributes, generate the class "cats.h" and "cats.m".
  - I write down the code to read and write on this entity => No problem everything works well.</p>
  
  <ul>
  <li><p>At this point I made a mistake by deleting the file "animals.xcdatamodeld" manually... I recreate it with the same name and add a new entity <code>Dogs</code> with its attributes and generate the associated class.</p></li>
  <li><p>That's where the problem is, when I build and run the error message comes : <code>+entityForName: could not locate an entity named 'Dogs' in this model.</code> FYI, the read/write on <code>Cats</code> is still ok.</p></li>
  </ul>
  
  <p>I have no idea why this error appears... I did not change anything on the App Delegate. I found very little information online related to that issue.
  This only thing I found was that maybe the model needs to be versioned when updated => Can someone explain that a lil bit please ?
  Anyway the model does not seem to have been updated when I added the new entity... </p>
  
  <p>Thx.</p>