Only files in the folder entered by the app user are copied.
Reference
https://www.googleapis.com/auth/drive
https://www.googleapis.com/auth/script.scriptapp
https://www.googleapis.com/auth/spreadsheets
https://www.googleapis.com/auth/userinfo.email
Reference
developers.google.com/identity/protocols/googlescopes
script.google.com/macros/s/AKfycby5ZB3-jSpoRwBcd7vrapAgxvx0UV0UG6pfGPhPJ97k6TZ7VTTC/exec
Type init or resume in the Source input box and click the Submit button.
deleteAllProperties()
https://developers.google.com/apps-script/reference/properties/properties.html#deleteAllProperties()
deleteTrigger(trigger)
https://developers.google.com/apps-script/reference/script/script-app#deleteTrigger(Trigger)
File Iterator
developers.google.com/apps-script/reference/drive/file-iterator
Creates a copy of the file in the destination directory.
developers.google.com/apps-script/reference/drive/file#makecopydestination
gSubfolder is a folder in Google Drive.
https://drive.google.com/drive/folders/0B_MA3GXgQ1ulQXBESW1pcFQxQzA