public class MainActivityModel implements MainActivityContract.Model {

    @Override
    public Disposable fetchDataFromServer() {
        return getObservable().subscribeWith(MainActivityPresenter.getObserver());
    }

    private Single<List<MenuComponent>> getObservable() {
        return RetrofitClient.getInstance().create(Api.class)
                .getMenuComponents()
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread());
    }
}