title: Add NSNumber 0 to NSDictionary
body: <p>I need to create a dictionary with for a search, based on IDs, but if no ID gets selected, 0 has to be stored.</p>
  
  <p>Now I can obviously do it like this:</p>
  
  <pre><code>NSNumber* cityID;
  NSNumber* zoneID; //These two do get value, just showing for their class
  NSDictionary *cityDictionary = @{@"CityID": [NSNumber numberWithInt:(int)cityId], @"CityZoneID": [NSNumber numberWithInt:(int)zoneId]};
  </code></pre>
  
  <p>I feel it's really messy like that. It gets cast to <code>int</code>, then turned back to <code>NSNumber</code>...</p>