How does one transfer files to S3 from heroku rails 3 AWS v1

In my rails 3 app I'm generating a file when a user does an action. This file needs to be permanent. So this file needs to be stored in some place like S3 AWS. What is the simplest way to do this using S3 AWS (aws-sdk v1)?

The image its genererated using the gem barby (http://ift.tt/1wTq278), so the user doesn't need to upload it.