Add Common Functions to Extending index

MGatner · web-flow · commit 2450658e574d · 2019-08-28T09:05:39.000-04:00
diff --git a/user_guide_src/source/extending/index.rst b/user_guide_src/source/extending/index.rst
@@ -8,6 +8,7 @@ CodeIgniter 4 has been designed to be easy to extend or build upon.
     :titlesonly:
 
     core_classes
+    common
     events
     basecontroller
     contributing
