Rubber-less deployment

Removed Rubber and replaced with Capistrano 3 as addressed in #42. Custom tasks to set up nginx and unicorn. Configuration is very basic and not optimized for performance. Some features are missing. Currently, the database is running on a remote server since there is no postgresql on servers provisioned by TMCYF::Skeleton. This PR is mostly a proof of concept.


Todo:

MVP
- [x] command to test if file exists
- [x] replace hardcoded values with variables
- [x] migration tasks
- [x] SSL management tasks
- [x] force SSL over all connections

Next iteration
- [x] fix desc naming - @stijlist
- [x] strengthen nginx SSL configs
- [ ] back up and restore database tasks
- [x] log rotation tasks
- [ ] scaling tasks
- [x] deployment notifications
- [x] rake task to set IP address of deployment
- [ ] fix error on cap <stage> deploy:check