title: Paperclip preview files before downloading, also generate share link
body: <p>I am starting up with rails and was going thru the <a href="http://codyaray.com/downloads/2012/03/How-to-Build-a-Dropbox-like-Sharing-App-using-Ruby-on-Rails.html" rel="nofollow">sharebox-tutorial</a>.<br>
  Now is it possible with paperclip to first preview the uploaded files and then choose the download link, rather than the file directly being downloaded when link is clicked, as in the tutorial and elsewhere in the internet.</p>
  
  <p>Also, what will be the method to generate a share link unique to every friend email.</p>
  
  <p>While researching, i also found out that files should be uploaded in some other folder but public.<br>
  how is it different from storing the files in public folder with the url hashed. the hash url is still accessible when user is logged out.</p>
  
  <p>UPDATE<br>
  the preview i am referring to should be after uploading.</p>