Coding Dojo: Social Network Kata

In this coding dojo, we will practice Behaviour-Driven Development
(https://en.wikipedia.org/wiki/Behavior-driven_development).

We'll try a new format:

• Explain the problem
• Work on it for 45 minutes
• Discuss altogether for 10-15 minutes, aligning our solution
• Work on it for the rest of the time.

Link: http://kata-log.rocks/social-network-kata