def full_name
      display_name_parts = [first_name, last_name].compact
      if display_name_parts.empty?
        username
      else
        display_name_parts.join(' ')
      end
    end
def full_name
      display_name_parts = [first_name, last_name].compact
      if display_name_parts.empty?
        username
      else
        display_name_parts.join(' ')
      end
    end
A display-friendly name for this user.  Uses `first_name` and
 `last_name` if available, otherwise it just uses the username.

 @return [String]