added local website build instructions for Jekyll website

Author: daniel-roesler

website/README.md

@@ -1,2 +1,37 @@
 This folder contains the code for our website:
 [https://cds-registration.lfenergy.org/](https://cds-registration.lfenergy.org/)
+
+
+## How to run your own copy of this website
+
+* On Ubuntu 24.04+ or Debian 13+, install `jekyll`.
+
+```
+sudo apt install jekyll
+```
+
+* Navigate to this website's folder in the repo.
+
+```
+cd website/
+```
+
+* Copy the specifications from the base repo folder to the website include folder.
+
+```
+cp ../specifications/cds-wg1-01.md _includes/spec_copies/placeholder_cds-wg1-01.md
+cp ../specifications/cds-wg1-02.md _includes/spec_copies/placeholder_cds-wg1-02.md
+```
+
+* Run the jekyll server, which builds the website and starts serving it on https://localhost:4000/
+
+```
+jekyll serve
+```
+
+* Done!
+
+**Note:** If you want to make changes to the specifications themselves (to make a pull request, etc.), you need to modify them in the `specifications/` folder, not the `spec_copies/` folder.
+Then, you will need to re-copy them to the `spec_copies/` folder for the changes to show up on your local website.
+Finally, when you're done with your changes, you need to commit changes in the `specifications/` folder and not commit any changes to the `spec_copies/` folder.
+Our automated build process for the official website will automatically copy over the specifications when a new version is built.