This code is tested, but it still has bugs. I would not suggest using this in a production environment

Directions For Use

1. Derive your Managed Object (in which you want to add an array) from the MRManagedObjectWithArray class.
2. Add an Transformable attribute (with Value Transformer MRManagedObjectWithArrayTransformer) for each array that you wish to add.
3. In your app delegate's applicationDidFinishLaunching, register the custom Value Transformer by calling [MRManagedObjectWithArrayTransformer registerTransformer];
4. Access your arrays with arrayForKey and mutableArrayForKey methods.

For example,

// In person.h
@property (nonatomic, retain) id beers;
..
// In person.m
@dynamic beers;
..
..
// Now use and abuse!
Person * you = [TheAlphaAndTheOmega sharedInstance];
[[you mutableArrayForKey:@“beers”] addObject:[Beer pint]];
if( [[you arrayForKey:@“beers”] count] > 7 )
 NSThink(@“I'm drunk!”);