Ember Select to Update Model onChange

I have an Ember HBS template form with input and select fields. Input fields use a 'value' argument set to model.someField. When a user changes the input value, the model also gets changed and then shows there are changedAttributes staged.

I want to do this exact same thing with a select, but when I change the select value, the model.someField isnt getting updated automatically. What's the right way to do this?

I'm using Ember 2.9.