title: Create custom GitHub emojis
body: <p>GitHub seems to have a rich set of emojis it supports.</p>
  
  <p><a href="https://gist.github.com/rxaviers/7360908" rel="nofollow noreferrer">https://gist.github.com/rxaviers/7360908</a></p>
  
  <p>I am looking for a green triangle face down.</p>
  
  <p>There is a red triangle face down, however, I am looking for precisely this, but in green. 
  </p>
  
  <p>It's code is</p>
  
  <pre><code>:small_red_triangle_down:
  </code></pre>
  
  <p>I. naively, tried doing <code>:small_green_triangle_down:</code> but that doesn't seem to be defined. Is there a way I can get a green colored triangle face down in GitHub ?</p>