ci: add link to MIT's "missing semester" resources

Author: calcmogul

ci/index.html

@@ -231,6 +231,8 @@ <h3 id="Graphical_user_interfaces">Graphical user interfaces</h3><a href=
       <p>Introduces designing graphical user interfaces with the Qt graphics
       toolkit.</p>
     </details>
+    <p><a href="https://missing.csail.mit.edu/">The Missing Semester of Your CS
+    Education</a></p>
     <h2 id="Lesson_plan">Lesson plan</h2>
     <h3 id="Offseason">Offseason</h3>
     <ul>