title: Draw vertical line on specific date
body: <p>I want to draw vertical line for example on the day specific start. </p>
  
  <p>In manual there is example:</p>
  
  <p><code>plot(timestamp(2016, 01, 19, 09, 30),linewidth=3,color=green)</code></p>
  
  <p>But this drawing horizontal line instead of vertical. </p>
  
  <p>Thanks for help.</p>