Remove mention of not-written part 5 of the tutorial
Remove mention of not-written part 5 of the tutorial

ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,0x80/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,fk/gatsby,0x80/gatsby,fk/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,fk/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,mingaldrichgan/gatsby