title: Amazon S3 integration on per user basis
body: <p>I have a web-app where I store user upload files, I am currently using my own S3 account to store the files. The file sizes are getting large so I want to develop a solution where each user can provide me with his S3 bucket keys and all the files that he owns are store in his own s3 bucket.</p>
  
  <p>I need some suggestions with the following ?</p>
  
  <p>1- What should I ask the user to provide me ? S3 bucket keys ? Is bucket name also required ?
  2- How can I verify that the provided keys are valid ?
  3- What do I need to do to upload/download files from the user's S3 bucket. will normal S3 operations work ?
  4- Any examples or documentation you can point me to ?</p>
  
  <p>I am using Ruby on Rails and S3+PaperClip gems to upload files right now.</p>
  
  <p>Thanks</p>