gistfile1.txt

    RKObjectMapping *mapping = [RKObjectMapping mappingForClass:[self class]];
    [mapping addAttributeMappingsFromDictionary:@{
     @"access_token": @"accessToken",
     @"access_token" : @"identifier",
     @"refresh_token": @"refreshToken",
     @"status.errorCode": @"errorCode",
     @"status.message": @"message",
     @"username": @"username",
     }];