r2

Fixed

• Link Chapter 6 code to the correct v0.1.0 tag, not the outdated v0.0.3 (@jrnt30
  in GraphQLGuide/guide#35)
• Update POST request to use valid JSON (@spiffcs in #6)
• Add missing prop-types import (#8)

Changed

• Switched to https GitHub URLs instead of git@ SSH URLs (@intengodev a14d458)