Fix missing property app_id

Screenshots

This plugin only inserts the required property with the given app_id. You have to create a facebook app to get the app_id! To create a facebook app, visit https://developers.facebook.com/ Register or Login to your account. Click My Apps, then click Create to create a new App When the app is created and you are in the app dashboard click settings and select Basic That is the App ID you need to copy and past in the field below