-record(credential, {
    service = "" :: string(),
    username = "" :: string(),
    password = "" :: string()
}).

-record(employee, {
    % field name ['=' default_value] ['::' spec]
    first_name :: string(),
    last_name :: string(),
    hire_date = calendar:universal_time() :: datetime(),
    is_awesome = true :: boolean(),
    employee_number = 0 :: integer(),
    credentials = [] :: [#credential{}]
}).