Update table of contents

Author: sebastiaanluca

README.md

@@ -19,6 +19,12 @@ Sets the date of fields to the current date and time if an inputted counterpart
 - [Requirements](#requirements)
 - [How to install](#how-to-install)
 - [How to use](#how-to-use)
+    - [Saving dates](#saving-dates)
+    - [Clearing saved values](#clearing-saved-values)
+    - [Retrieving values](#retrieving-values)
+        - [Retrieving fields as booleans](#retrieving-fields-as-booleans)
+        - [Retrieving fields as datetimes](#retrieving-fields-as-datetimes)
+    - [Array conversion](#array-conversion)
 - [License](#license)
 - [Change log](#change-log)
 - [Testing](#testing)