Update Dockerfile

Dockerfile

@@ -2,6 +2,7 @@ FROM hugomods/hugo:exts-0.124.0 AS builder
 WORKDIR /srv/hugo
 COPY . .
 RUN chown 1000:1000 -R /srv/hugo
+ARG BASE_URL
 RUN hugo --gc --minify --cleanDestinationDir --baseURL "${BASE_URL}"
 
 FROM nginx:alpine