add a script for update

Dockerfile

@@ -5,7 +5,7 @@ FROM hugomods/hugo:nightly
 RUN apk add --no-cache nodejs npm
 
 # Install Sass (Dart Sass) globally
-RUN npm install -g sass
+RUN npm install -g sass yarn
 
 # Set the working directory inside the container
 WORKDIR /app
@@ -18,7 +18,7 @@ RUN chmod +x scripts/build.sh
 
 # Install Node.js dependencies if any (e.g., for fetch-wordpress.js)
 # Assuming package.json exists and has dependencies
-RUN if [ -f package.json ]; then npm install; fi
+RUN if [ -f package.json ]; then yarn install; fi
 
 # Ensure /usr/local/bin is in PATH for the CMD
 ENV PATH="/usr/local/bin:$PATH"