How can I add default values for ember has many relationship?

I'm using Ember 2.5.0 and I have two models service and availability which looks like:

// availability
import DS from 'ember-data';

export default DS.Model.extend({
  day: DS.attr('string'),
  enabled: DS.attr('boolean'),
  startAt: DS.attr('string'),
  endAt: DS.attr('string'),
  service: DS.belongsTo('service')
});

And service which looks like:

import DS from 'ember-data';

export default DS.Model.extend({
  name: DS.attr('string'),
  description: DS.attr('string'),
  availabilities: DS.hasMany('availability',
    {
      defaultValue:
        [
          {
            day: 'saturday',
            enabled: false,
            startAt: '',
            endAt: ''
          },
          {
            day: 'sunday',
            enabled: false,
            startAt: '',
            endAt: ''
          }
        ]
    }
  )
});

As you can see I was trying to use defaultValue but with no luck. For new route I want to set default values if we are creating a new service record.

Any help is appreciated.