Update dependencies.
Simplify database connection management.

Bluebird has support for disposers built-in.
Fix submission uploads without custom thumbnails.

This saves thumbnail cropping for later and also moves the handling of
empty uploads into media.upload() so they don’t fail identification.
List more dependencies and details.
Use Vagrant.
Remove Secure flag from insecure cookies.
Forward Host header; redirect with forwarded protocol.

This fixes redirects on Vagrant.
Add a helpful Vagrant post_up_message.
Use forever for automatic restarting.

This matches up with the playbook deployment, and also reloads properly (by
polling) in a Vagrant VM.
Use lib/db for migrations.
Simplify rate limit violation responses.
Move out of Promise constructor callbacks.
Promisify createGuestToken().
Move file handling into form-session.

This greatly simplifies controllers accepting file uploads.
Upload limits haven’t been implemented yet.
Make .foreverignore ignore files.
Slightly more correct `rel`s.