Override contents of generated `application.yml`

[bigzoo]

Is it currently possible to control what in the application.yml file after running figaro install? I've looked around docs but can't find anything conclusive...
Eg instead of it looking like:

# Add configuration values here, as shown below.
#
# pusher_app_id: "2954"
# pusher_key: 7381a978f7dd7f9a1117
# pusher_secret: abdc3b896a0ffb85d373
# stripe_api_key: sk_test_2J0l093xOyW72XUYJHE4Dv2r
# stripe_publishable_key: pk_test_ro9jV5SNwGb1yYlQfzG17LHK
#
# production:
#   stripe_api_key: sk_live_EeHnL644i6zo4Iyq4v1KdV9H

having custom contents like:

# custo_key_1: "2954"
# custom_key_2: 7381a978f7dd7f9a1117