SSH Keys

[dshoreman]

For users that should be able to login over SSH, we need a way to populate the authorized_keys file with one or more public keys.

In order to pull private Git repos, we'll also need to be able to generate new key pairs.

Not really sure how to go about this in the UI. Maybe two separate sections to distinguish permitted login keys from private/public keys for the user itself? Could have it all on one 'SSH Keys' tab with 'Add Public Key' and 'Create Keypair' buttons, but that could be a bit confusing with both mixed in one list.