title: What are the default gems of Mac OSX 10.11?
body: <p>I tried to study Ruby on Rails and followed a tutorial. However, I think I missed a part and I can't proceed to the next step in the tutorial, so I plan to uninstall things, including the gems I installed, and start all over again.</p>
  
  <p>I installed Ruby using Homebrew, because people say it's best not to mess with the Ruby that comes with macOS. Then, I uninstalled it again using <code>brew uninstall ruby</code>.</p>
  
  <p>After doing that, I ran <code>gem list</code> and this came out:</p>
  
  <pre><code>*** LOCAL GEMS ***
  
  - bigdecimal (1.2.0)
  - builder (3.2.2)
  - CFPropertyList (2.2.8)
  - io-console (0.4.2)
  - json (1.7.7)
  - libxml-ruby (2.6.0)
  - minitest (4.3.2)
  - nokogiri (1.5.6)
  - psych (2.0.0)
  - rake (0.9.6)
  - rdoc (4.0.0)
  - sqlite3 (1.3.7)
  - test-unit (2.0.0.0)
  - thor (0.19.1)
  </code></pre>
  
  <p>What are the gems (if any) that come with macOS system Ruby?</p>