title: CoreData: error: Failed to call designated initializer on NSManagedObject class
body: <p>I have a little damn problem with CoreData. I want to insert a new Object, so I first have to create one. This is done by that code:</p>
  
  <pre><code>Challenges *newChallenge = [[Challenges alloc] init];
  [newChallenge setName:@"TestChallenge"];
  [newChallenge setRounds:[[NSNumber alloc] initWithInt:12]];
  [newChallenge setShots:[[NSNumber alloc] initWithInt:5]];
  [newChallenge setDate:[NSDate date]];
  </code></pre>
  
  <p>But however after the alloc init I get this error:</p>
  
  <pre><code>CoreData: error: Failed to call designated initializer on NSManagedObject class 'Challenges'
  </code></pre>
  
  <p>What the hack is going wrong?</p>