title: angular-chart add horizontal line
body: <p>I want add horizontal line like here [<a href="https://stackoverflow.com/questions/31092489/chart-js-draw-horizontal-line][1]">Chart.js - draw horizontal line</a> to my angular-chart.js (if I understand right, what I need to do is to extend the line type chart).</p>
  
  <p>How and where I should do it (write own directive, try extend the char.js in angular .config)?</p>