addPerson(deptid) {
        var newID = Math.random().toString(16).slice(2);
        var newPerson = this.store.createRecord('person', {
            name: "Person Name",
            id: newID,
            devices: []
        }).save();

        this.store.find('department', deptid).then(function (department) {
            department.pushObject(newPerson);
        });
     }

this.store.find('department', deptid).then(function (department) {
        department.get('peeps').pushObject(newPerson);
    });