title: With Rails Paperclip gem, how to temporarily save the uploaded file if the model is invalid
body: <p>I am using the paperclip gem to attach files to models. When you upload a file using Paperclip, the file is saved ONLY when the model is saved. Thus, if the model is invalid, the uploaded file is not saved. Is there a way to temporarily save the uploaded file, so that the user doesn't have to upload the same file if the model is invalid?</p>