anchor.diff:      var h = d.score;
       // breakdown
       t.selectAll(".contributor")
  -      .attr("transform", "translate(0,"+y(h)+")");
  +      .attr("transform", "translate(0," + y(h) + ")");
       t.selectAll(".contributor-bar")
         .attr("height", 0);
       // label
  
positive.code:   .data(function(d) { return d.contributors; })
    .enter().append("g")
    .attr("class", "contributor")
    .attr("transform", "translate(0,"+height+")");
  
  //collapse groups
  repo_groups.each(function(d) {
    var h = d.score;
    d3.select(this).selectAll(".contributor")
      .attr("transform", "translate(0,"+y(h)+")");
  });
  
  contributor_groups
  
negative.code: var height = 300 - margin.top - margin.bottom;
  
  var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], .1)
    .domain(repos.map(function(d) { return d.name; }));
  
  var y = d3.scale.linear()
    .range([0, height])
    .domain([0, d3.max(repos, function(d) { return d.score; })]);
  
  var colors = d3.scale.ordinal()
    .range(['#1976d2','#2196f3', '#64b5f6','#bbdefb'])
  