Paperclip Broken Attachment finder

t will scan ALL attachments in application & check to if they do really exists on storage location.
if the file is not found, it will log as error on STDERR.

The way you want to this is:

```sh
$ rake broken_links_check 2> path/to/file
```

The code might need some cleanup, will do that but want to see if you guys think its a good idea?