api

- GET /uuid/:uuid
- skip verify_authenticity_token for POST /movies/
- POST movie with remote file urls
- ping callback url when conversion complete(web hook)
  - passing movie uuid

client implementation: https://github.com/shin1ohno/jani-converter_client/pull/1/files

---------------

@l15n please review
[nit] I would prefer
``ruby
if @movie
  respond_with @movie
else
  head :not_found
end
```

instead of using `return` to shortcut