This is a demo that tries to show many facets of Rye language in practice. It loads a csv file, then manipulates the loaded Spreadsheet datatype. Next it creates a HTTP server, that returns specific data from the spreadsheet. This server is created in a goroutine, so we can continue using our Rye shell. So next we make a HTTP GET request to our server and receive the JSON data. We again manipulate this data and turn it into a list of emails. We then use Postmark API to create and send email to the email in the list.