Restkit not mapping back to UserToken object

gistfile1.c

- (void) postLogin
{
    
    //Setup Login data
    UserLogin *l = [[UserLogin alloc] initWithUsername:[usernameField text] andPassword:[passwordField text]];
    
    //Setup Routes
    RKObjectRouter *router = [RKObjectManager sharedManager].router;
    [router routeClass:[UserLogin class] toResourcePath:@"/api/v1/login" forMethod:RKRequestMethodPOST];
    
    //Setup Token Mapping
    RKObjectMapping *UserTokenMapping = [RKObjectMapping mappingForClass:[UserToken class]];
    [UserTokenMapping mapKeyPath:@"authentication_token" toAttribute:@"token"];
    //[[[RKObjectManager sharedManager] mappingProvider]setMapping:UserTokenMapping forKeyPath:@""];
    [[RKObjectManager sharedManager].mappingProvider registerMapping:UserTokenMapping withRootKeyPath:@""];
    
    //Setup Mapping for UserLogin class
    RKObjectMapping *UserLoginMapping = [RKObjectMapping mappingForClass:[UserLogin class]];
    [UserLoginMapping mapKeyPath:@"login" toAttribute:@"userName"];
    [UserLoginMapping mapKeyPath:@"password" toAttribute:@"passWord"];
    [[RKObjectManager sharedManager].mappingProvider registerMapping:UserLoginMapping withRootKeyPath:@""];
    
    [[RKObjectManager sharedManager] postObject:l delegate:self];
    
}