Fix readme

Author: adamchalmers

README.md

@@ -1,3 +1,10 @@
+Our guide to KCL.
+
 Read it [here](https://zoo.dev/docs/kcl-book/intro.html).
-Use `mdbook serve` to spin up local copy
-Use `mdbook build` to compile static site
+
+## Developing
+
+If you're working on the KCL book:
+
+ - Use `mdbook serve` to spin up local copy
+ - Use `mdbook build` to compile static site