title: Chart.js - draw horizontal line
body: <p>I would like to draw a horizontal line in a chart using <a href="http://www.chartjs.org/" rel="noreferrer">Chart.js</a>. But I'm not able to do it.</p>
  
  <p>I've read this question - <a href="https://stackoverflow.com/questions/30256695/chart-js-drawing-an-arbitrary-vertical-line?rq=1">Chart.js — drawing an arbitrary vertical line</a> - but I can't transform the code for drawing <strong>horizontal lines</strong> not vertical.</p>
  
  <p>I hope you can help me (especially potatopeelings :)).</p>