Now, let's create the relationships by adding the following array to the bottom of app.js. Note that the attributes must be source and target, in order for D3 to do its magic:
var linksData = [
{"source": "Charlie", "target": "Mac"},
{"source": "Dennis", "target": "Mac"},
{"source": "Dennis", "target": "Dee"},
{"source": "Dee", "target": "Mac"},
{"source": "Dee", "target": "Frank"},
{"source": "Cricket", "target": "Dee"}
];