You can add push notifications to your Ionic app by adding the Push plugin (https://github.com/phonegap-build/PushPlugin) and configuring it. Or you can use the push template from Ionic to do so:

ionic add ionic-service-core
ionic add ionic-service-push
ionic start myPushApp push
cd myPushApp
ionic plugin add https://github.com/phonegap-build/PushPlugin.git
ionic upload

Now, you can head back to the app.ionic.io page and click on the setting for the preceding app. In www/js/app.js, you will find the config section, which you can update with the values from the app settings page:

.config(['$ionicAppProvider', function($ionicAppProvider) {
  // Identify app
  $ionicAppProvider.identify({
    // The App ID for the server
    app_id: 'YOUR_APP_ID',
    // The API key all services will use for this app
    api_key: 'YOUR_PUBLIC_API_KEY'
  });
}])

Then, you can follow the Android Push setup guide (http://docs.ionic.io/v1.0/docs/push-android-setup) or the iOS push setup guide (http://docs.ionic.io/v1.0/docs/push-ios-setup) to implement the Push notifications.