func startSubscription() {
    let settingsNavigationVC = self.tabBarController?.viewControllers![2] as! UINavigationController
    let settingsVC = settingsNavigationVC.topViewController as! SettingsViewController
    settingsVC.selectedUser.subscribe(onNext: { [weak self] user in
        self?.userToShow = user
    }).disposed(by: disposeBagForFirst)
    }