add command to install authy-ssh in the user's authorized keys
add command to install authy-ssh in the user's authorized keys

Signed-off-by: David A. Cuadrado <9e86d6d2f3901859480d56aec66da07500c6a5df@gmail.com>

wikijm/authy-ssh,jadams/mailgun-ssh,wikijm/authy-ssh,authy/authy-ssh,adumont/authy-ssh,adumont/authy-ssh,authy/authy-ssh