title: Overlaying histogram using rbokeh
body: <p>I am trying to create an overlaying histogram using <code>rbokeh</code>.</p>
  
  <p>An example can be found below:</p>
  
  <pre><code>library(rbokeh)
  # Simple approach:
  h1 &lt;- figure(width = 600, height = 400) %&gt;%
              ly_hist(eruptions, data = faithful, breaks = 40, freq = T)
  
  # Overlaying approach:
  faithful$grouper &lt;-  sample(c("A","B"), 272, replace = T)
  
  h2 &lt;- figure(width = 600, height = 400) %&gt;%
              ly_hist(eruptions, data = faithful, breaks = 40, freq = T, color = grouper)
  </code></pre>
  
  <p>I am not sure whether the <code>color</code> option would provide this functionality. </p>
  
  <p>Thanks for your help.</p>