docs: add build instructions to README

README.md

@@ -0,0 +1,18 @@
+# quickshell-docs
+
+Documentation for [quickshell](https://git.outfoxxed.me/outfoxxed/quickshell).
+
+# Building the documentation
+
+The docs depend on:
+- just
+- hugo
+- rust
+
+To build the documentation you must be in a subdirectory of the main quickshell repo,
+which is where the submodule clones this repo.
+
+Run the following command to build and serve the docs locally:
+```
+$ just serve
+```