[Feature Request] specify which variable to be updated by getmdl-select

[LeMecAvecLaCageAHamster]

Hi @randrianov ,

I'm using your library in my Angular 2+ project and I'd like to know if you could add this useful feature to your project.

<input value="" type="hidden" name="country" [(ngModel)]="myCountryAttribute" />

Thanks in advance.

Best regards,