Duplicate command line options are interpreted as an array

[garnold]

For example, when specifying the --ssh-key argument on the command line twice, an array is stored in ssh_key:

$ overcast instance import foo 1.2.3.4 --ssh-key bar --ssh-key baz
Using "default" cluster.
Instance "foo" (1.2.3.4) has been imported to the "default" cluster.

$ overcast info foo
Using /Users/garnold/.overcast/clusters.json

foo
  ip: 1.2.3.4
  name: foo
  ssh_port: 22
  ssh_key:
    0: bar
    1: baz
  user: root
  password: ""