How to create dynamic model in ember data

I am trying to create a dynamic ember data models.I have tried this code in route\user like:

var tableColumns = {
   name: DS.attr('string'),
    surname: DS.attr('string')
};
let store = this.get('store');
Ember.getOwner(store).register('model: user', DS.Model.extend(tableColumns));

after creating a model for this.store.findAll(user). but it's not working and it shows model user is not defined.