This is a legitimate question, so I don't think downvotes are warranted. Elon Musk may want to live on Mars (and in fact I have at least one friend who would abandon everything and take a one-way ticket to Mars in a heartbeat), but the sentiment expressed here of using a Martian population as insurance against an Earthborne cataclysm requires a functioning, self-sufficient civilization composed of more than just a cadre of explorers and thrill-seekers.
You'll need to find a way entice doctors, farmers, miners, and other specialized professions to leave everything behind and consign themselves to death on a dark and barren rock. Historically, colonists have been motivated to such lengths for religious and political reasons. For example, perhaps libertarians will flock to Mars for freedom from oppressive governments. (Hey Bioshock developers: hint hint.)