anchor.diff:  
   All projects
   
  +<%
  +  date_chart_options = {
  +    scales: {
  +      xAxes: [{
  +        type: 'time',
  +        unit: 'day',
  +        unitStepSize: 1,
  +        time: {
  +          displayFormats: {
  +             'day': 'YYYY-MM-DD'
  +          } } }]}
  +  }
  +%>
  +
   <%=
     # Show a chart with just total # projects.
     series_dataset = ProjectStat.all.reduce({}) do |h,e|
       h.merge(e.created_at => e.percent_ge_0)
     end
  -  line_chart series_dataset
  +  line_chart series_dataset, library: date_chart_options
   %>
   
   <br><br><br>
  
positive.code:                 data: moving_average_dataset,
                  library: {borderDash: [5,5]}}
    end
    line_chart dataset, colors: ['green', 'darkgreen', 'blue', 'darkblue']
  %>
  
  <br><br><br>
  
negative.code:     end
      {name: '>=' + minimum.to_s + '%', data: series_dataset}
    end
    line_chart dataset, library: date_chart_options
  %>
  
  <br><br><br>
  