Merge pull request #45 from csmith/master

Move SSH key into a file.
Add backuppc user
backuppc-user -> backuppc-client
Merge pull request #46 from ShaneMcC/backuppc

Add backuppc user
Don't start using feedback user before it exists.
Merge pull request #47 from greboid/feedback-site

Don't start using feedback user before it exists.
Use php5-fpm-nginx role
Merge pull request #48 from greboid/feedback-site

Use php5-fpm-nginx role.
Use new php role.
No need for double dependency
Merge pull request #49 from greboid/feedback-site

Use new php role.
Sentry needs sentry :-)
Add vars for sentry deployment.

This includes a vault-encrypted vars file containing the GitHub
client ID and secret.
Stick the command to run playbooks in README.