Adding data for relationships

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"}
];