D3 Force Layout with Zoom - scale to container

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.17/d3.min.js"></script>
<h1>D3 force layout with zoom needs to scale within this container:</h1>
<div class="viz-chart">
  <svg id="chart"></svg>
</div>

CSS

#chart {
  border: grey solid 1px;
  cursor: move;
  overflow: hidden;
}

.link {
  stroke: #999;
  stroke-opacity: 0.6;
  stroke-width: 2;
}

JavaScript

var graph = 
{
  "nodes":[
		{"name":"1","rating":90,"id":2951},
		{"name":"2","rating":80,"id":654654},
		{"name":"3","rating":80,"id":6546544},
		{"name":"4","rating":1,"id":68987978},
		{"name":"5","rating":1,"id":9878933},
		{"name":"6","rating":1,"id":6161},
		{"name":"7","rating":1,"id":64654},
		{"name":"8","rating":20,"id":354654},
		{"name":"9","rating":50,"id":8494},		
		{"name":"10","rating":1,"id":6846874},
		{"name":"11","rating":1,"id":5487},
		{"name":"12","rating":80,"id":"parfum_kenzo"},
		{"name":"13","rating":1,"id":65465465},
		{"name":"14","rating":90,"id":"jungle_de_kenzo"},
		{"name":"15","rating":20,"id":313514},
		{"name":"16","rating":40,"id":36543614},
		{"name":"17","rating":100,"id":"Yann_YA645"},
		{"name":"18","rating":1,"id":97413},
		{"name":"19","rating":1,"id":97414},
		{"name":"20","rating":100,"id":976431231},
		{"name":"21","rating":1,"id":9416},
		{"name":"22","rating":1,"id":998949},
		{"name":"23","rating":100,"id":984941},
		{"name":"24","rating":100,"id":"99843"},
		{"name":"25","rating":1,"id":94915},
		{"name":"26","rating":1,"id":913134},
		{"name":"27","rating":1,"id":9134371},
    {"name":"21","rating":1,"id":9416},
		{"name":"22","rating":1,"id":998949},
		{"name":"23","rating":100,"id":984941},
		{"name":"24","rating":100,"id":"99843"},
		{"name":"25","rating":1,"id":94915},
		{"name":"26","rating":1,"id":913134},
		{"name":"27","rating":1,"id":9134371},
    {"name":"21","rating":1,"id":9416},
		{"name":"22","rating":1,"id":998949},
		{"name":"23","rating":100,"id":984941},
		{"name":"24","rating":100,"id":"99843"},
		{"name":"25","rating":1,"id":94915},
		{"name":"26","rating":1,"id":913134},
		{"name":"27","rating":1,"id":9134371},
    {"name":"21","rating":1,"id":9416},
		{"name":"22","rating":1,"id":998949},
		{"name":"23","rating":100,"id":984941},
		{"name":"24","rating":100,"id":"99843"},
		{"name":"25","rating":1,"id":94915},
		{"name":"26","rating":1,"id":913134},
		{"name":"27","rating":1,"id":9134371},
...