Add in additional manifest to setup postgres backups

![](http://24.media.tumblr.com/0e61d566c200332634ebc33b35b21c09/tumblr_n0cq1g8Ul31rjg379o1_500.jpg)

- Ensures that a directory *on the same box* is created
- Sets a job to run every 2 hours using pg_dump
- Uses a template I found on the www's: https://github.com/ckaenzig/puppet-postgresql/blob/master/templates/pgsql-backup.sh.erb
- **NB:** This pull request is not the whole story - we should push to a separate box, as described here:
  https://www.pivotaltracker.com/s/projects/911872/stories/65578342