Trigger login modal before performing action - Ember

I'm trying to figure out how to trigger my login modal before allowing user to create something.

Did some research, found that I could use beforeModel, but I'm concerned that would prevent user from seeing the entire route? I want the route to remain visible, just want the user to be triggered a login modal if not authenticated yet.

My template:

<div class="input-group input-group-lg center-block">
{{input class="form-control" type="text" value=newListTitle action="createList" placeholder="Create a Stack"}}
</div>

My route with the action:

import Ember from 'ember';

export default Ember.Route.extend({
    model: function() {
        return this.store.find('list');
    },

    actions: {
        createList: function() {
            var newListTitle = this.controllerFor('lists').get('newListTitle');
            //var user = this.get('session.user.displayName');
            var userId = this.get('session.user.uid');

            //var user = this.get('session.user');

            if (Ember.isBlank(newListTitle)) { return false; }

        //1
            var list = this.store.createRecord('list', {
                title: newListTitle,
                user: userId,
            });
...

Modal:

{{#modal-dialog title="modal" id="modal" action="close"}}
...

Thanks, I'd appreciate if you could point me in the right direction.