Google Apps Script File Upload UI Service Demo

In this script, we will use the Google spreadsheet to keep track of files uploaded to Google Sites' File Cabinets. There are four parts to this script:

1. Creating a File Upload form using the Google Apps script UIApp and the FileUpload UI
2. Adding a button to invoke the form from the Google Spreadsheet File Menu
3. Using the Sites Service to store the uploaded file to the Google Sites' File Cabinet
4. Using the Spreadsheet Service to save the URL to the Uploaded File in the active spreadsheet cell.