Add challenges

[antonmc]

Want to add the list of challenges that I've been thinking of so far - just to have a range. These are based on concepts or ideas that I've seen in real life.

• [x] Bike to Work
• [x] Fit for Work
• [x] Stair Challenge
• [x] Life Insurance discount for runners
• [x] Half Marathon Qualifying

And a bonus one that I talked with @rvennam about to help the design team journey map, using Watson as a measurement of health rather than Healthkit on this occasion.

• [ ] Journaling for book tokens

In this case we'd be measuring personality insights from a series of journals. Just journaling would offer a reward, but PI markers may indicate suitability for job roles.