SSH Key management about trellis

[austinpray]

If we want to be super cool it could automatically grab public keys based on github usernames as an additional configuration option.

https://github.com/austinpray.keys

I have set up servers to use curl to grab my github public keys before, it's pretty simple to do with ansible as well.

[swalkinshaw]

GitHub keys is a great idea.

Ideally adding ssh keys would be a more general thing and taken out of the capistrano role. I'd like to be able to say: add these keys for these users.

[swalkinshaw]

GitHub SSH keys were added in #95.