docs(recommended-reading): added pro git (#253)

docs/xx-appendices/recommended-reading/index.mdx

@@ -13,10 +13,6 @@ This section is being expanded regularly, so check back often to find more recom
 
 Some great books and articles for specific topics are listed below.
 
-TODO TODO TODO
-
-There are numerous articles and online books on Git - I also recommend the excellent book "Pro Git" by Scott Chacon and Ben Straub.
-
 ## The Future of the Shell
 
 - [The Changelog - Making the command line glamorous](https://changelog.com/gotime/222)
@@ -28,7 +24,6 @@ There are numerous articles and online books on Git - I also recommend the excel
 
 Each of these books would make a great addition to your bookshelf if you are a technologist. Many of these books I have read multiple times and still go back to as a reference.
 
-
 <table>
   <tr>
     <td><img style={{width: '480px'}} alt="Book Cover Image: Applied Cryptography" src={require('./images/applied-cryptography.jpeg').default} /></td>
@@ -37,6 +32,13 @@ Each of these books would make a great addition to your bookshelf if you are a t
       <p>This is the absolute best book around on cryptography - from concepts, protocols all the way to advanced topics. There are code examples in C that allow you to really see how these concepts work in practice. This is an excellent book for someone who wants to learn about cryptography but also have the option to go deep into the topics that interest them.</p>
     </td>
   </tr>
+  <tr>
+    <td><img style={{width: '480px'}} alt="Book Cover Image: Pro Git" src={require('./images/pro-git-2.png').default} /></td>
+    <td>
+      <p><strong><a href="https://git-scm.com/book/en/v2">Pro Git - Scott Chacon and Ben Straub</a></strong></p>
+      <p>Superb book on Git, that is essential reading for the new user, but also goes into great depth on topics that will be relevant for expert readers. Should be on everyone's bookshelf.</p>
+    </td>
+  </tr>
 </table>
 
 ### [Shell Scripting by Jason Cannon](https://www.amazon.com/Shell-Scripting-Automate-Command-Programming-ebook/dp/B015FZAXU6)
@@ -60,6 +62,14 @@ This is a wonderful repository, which aims to help you "Master the command line,
 
 These resources are available online and are particularly useful.
 
+### [Command Line Interface Guidelines](https://clig.dev/)
+
+> An open-source guide to help you write better command-line programs, taking traditional UNIX principles and updating them for the modern day.
+
+This is an excellent online resource that describes the principles, but also practical patterns, that you can use to design CLI programs that interface well to other programs and make sense to human operators. This is great reading if you are building any kind of CLI app.
+
+https://clig.dev/
+
 ### The Missing Semester of Your CS Education
 
 The introduction in the site says it better than I could!