How can I install Ruby to be used as a notebook in the Jupyter Web UI (Mac OS 10.10.5)?
<p>I've found several pages that purport to tell me how to do this but I've had no success so far.</p>

<p>FYI, I've never used Ruby or any part of its ecosystem (Gem? That's clever!) so I'm swimming in a sea of new terminology and assumptions.</p>

<p>I have Jupyter 4.1.0 installed. When I boot it with <code>jupyter notebook</code> I get the web UI and under the "New" menu and under "Notebooks" I only see Python 2. I would really like to see "Ruby" like I do on the <a href="https://try.jupyter.org/" rel="nofollow">Try Jupyter</a> page.</p>

<p>I tried following the instructions on this page:
<a href="https://github.com/SciRuby/iruby/tree/master" rel="nofollow">https://github.com/SciRuby/iruby/tree/master</a>
It seemed to suggest that for an installation involving Python 2 I should use the installation instructions found on the <a href="https://github.com/SciRuby/iruby/tree/ipython2" rel="nofollow">IPython2 branch</a>. I t actually seemed to suggest that I should do that if I had IPython2. It seems I actually have IPython 4.1.2 but the first instruction set didn't work so. Furthermore, I don't actually understand how IPython factors into all of this as I started using Jupyter when it was already called Jupyter.</p>

<p>When I tried to follow the master branch instructions Gem told me</p>

<blockquote>
  <p>iruby requires Ruby version >= 2.1.0</p>
</blockquote>

<p>Apparently I have ruby version 2.0.0p481.</p>

<p>Then I wasn't sure how to upgrade ruby. Gem? Brew? Pip? Binary?</p>

<p>I was, eventually, able to install iruby version 1.9 with Gem but it didn't show up in the Jupyter UI. I restarted the Jupyter server, closed the terminal and started it again, etc with no success.</p>

<p>I'm going around in circles here and I'm sure it's slightly less complicated than it seems.</p>

<ul>
<li>Is there a config file somewhere that tells Jupyter which kernels to
load?</li>
<li>Is there a PATH variable that needs to contain the iruby binary?</li>
</ul>

<p>Also, unless this statement alludes to a serious misunderstanding somewhere, I'm not (yet) interested in Ruby on Rails. I'm under the impression that is some sort of framework that I may have use for some day. For now, I just want a little playground for ruby. (I know there are online ruby IDEs out there but I really like Jupyter and it seems like I can do it there. So I wanna!!)</p>

<p>Here is a summary of a few of my details so far.</p>

<ul>
<li>Mac OS 10.10.5</li>
<li>Python 2.7.11</li>
<li>Gem 2.0.14</li>
<li>IPython 4.1.2</li>
<li>Jupyter 4.1.0</li>
</ul>

<p>I have plenty of experience with Python.
I have zero experience with Ruby.</p>

<p>Thank you, in advance, for your help!</p>