Ember data subdocuments

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I see this documentation on serializers, which seems like the answer, but I can't get it to work. I just want a simple JSON object structure like this:

business-hours : {
    monday: {
        open: “24hr”,
        from: <some time>,
        to: <some time>
    },
    tuesday: {
        open: “closed”,
        from: <some time>,
        to: <some time>
    }
},

What's the move here?