How to boot Ubuntu from a second HDD connected to a laptop running Windows 8.1?

I have an Ubuntu with many dependencies, applications installed on my laptop. I am buying a new laptop with Windows 8.1. How can I bring the entire contents,installations of Ubuntu from my old laptop to the new laptop with out losing Windows 8.1? Is there anyway of taking image(snapshot) of Ubuntu, then bring it to the new laptop with 8.1. I don't want to wipe out Windows 8.1, or a clean installation of Ubuntu.