title: Upload files to dynamic folders using random string in models.Filefield 'upload_to' entry
body: <p>I am using <code>models.Filefield</code> to upload files to the server. When uploading a new file with name of an existing file, django append name with some random characters. But I need to retain filename. Hence I change <code>upload_to</code> entry in the <code>models.Filefield</code> to <code>upload_to='str(uuid.uuid4())'</code>. It works fine, but seldom the above problem occur. Is there any other methods to correct it ?</p>