RestKit RKObjectMapping вложенный json

Как я могу отобразить вложенный json ниже с помощью RestKit RKObjectMapping? Мне нужно только отобразить «данные». Мой текущий код ниже возвращает (null)-Спасибо!

{

    "sucess": true,
    "error": {
        "code": "",
        "message": ""
    },
    "data": [
        {
            "id": 1,
            "name": "Salad",
            "description": "Salad Desc",
            "category_id": 1
        },
        {
            "id": 2,
            "name": "Soup",
            "description": "Soup Desc",
            "category_id": 1
        },
        {
            "id": 3,
            "name": "Wrap",
            "description": "Wrap Desc",
            "category_id": 1
        },
        {
            "id": 4,
            "name": "Appetizers",
            "description": "Appetizers Desc",
            "category_id": 1
        }
    ]

} 

Class

@interface Subcategory : NSObject    
    @property (nonatomic, retain) NSNumber *subcategoryID;
    @property (nonatomic, retain) NSNumber *categoryID;
    @property (nonatomic, retain) NSString *name;
    @property (nonatomic, retain) NSString *description;
    @property (nonatomic, retain) NSString *thumbnail;
    @property (nonatomic, retain) NSArray *data;

ViewController

RKObjectMapping* mapping = [RKObjectMapping mappingForClass:[Subcategory class]];

RKObjectMapping* dataMapping = [RKObjectMapping mappingForClass:[Subcategory class]];
[dataMapping mapKeyPath:@"id" toAttribute:@"subcategoryID"];
[dataMapping mapKeyPath:@"category_id" toAttribute:@"categoryID"];
[dataMapping mapAttributes:@"name", @"description", nil];

[mapping mapKeyPath:@"data" toRelationship:@"data" withMapping:dataMapping];

[[RKObjectManager sharedManager] loadObjectsAtResourcePath:[NSString stringWith