discourse/app/assets/javascripts/admin/routes/admin_customize_route.js

/**
  Handles routes related to customization

  @class AdminCustomizeRoute    
  @extends Discourse.Route
  @namespace Discourse
  @module Discourse
**/ 
Discourse.AdminCustomizeRoute = Discourse.Route.extend({
  model: function() {
    return Discourse.SiteCustomization.findAll();
  },

  renderTemplate: function() {    
    this.render({into: 'admin/templates/admin'});
  }
});