Orphan list

First two tasks of PT story https://www.pivotaltracker.com/story/show/76239760

- [x] Create Orphan List model
- [x] Create new and index views for orphan lists
- [ ] Write cucumber features for testing orphan list creation and file upload 
- [ ] Switch to S3 for file storage
On further reflection, I see that factories wouldn't help that much here. It's just that seeing e.g. status code, which is essentially meaningless in this context, specified explicitly in a feature makes me want to start optimizing. Hopefully, much of this will be taken care of by using fixtures for our reference models.