gistfile1.m

[objectManager postObject:[User class] path:@"/users" parameters:@{@"user" : @{@"email" : @"test@example.com", @"password" : @"password"}} success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
    NSLog(@"success");
} failure:^(RKObjectRequestOperation *operation, NSError *error) {
    NSLog(@"failure");
}];