Fix deprecated syntax in asciinema.rb

Signed-off-by: Rogerio Prado de Jesus <rogeriopradoj@gmail.com>
Fix install command in asciinema.rb

Signed-off-by: Rogerio Prado de Jesus <rogeriopradoj@gmail.com>
Include minimal tests in asciinema.rb

Signed-off-by: Rogerio Prado de Jesus <rogeriopradoj@gmail.com>