docs: add deploy script for github pages

Author: thunderbiscuit

website/deploy/gh-pages.sh

@@ -0,0 +1,15 @@
+# This script will build the website and push it to the gh-pages branch,
+# publishing it automatically to https://bitcoindevkit.github.io/devkit-wallet/.
+
+set -euo pipefail
+
+just clean
+just build
+cd ./site/
+git init .
+git switch --create gh-pages
+git add .
+git commit --message "Deploy $(date +"%Y-%m-%d")"
+git remote add upstream git@github.com:bitcoindevkit/devkit-wallet.git
+git push upstream gh-pages --force
+cd ..