Attempt to fix build file permission issues.

bin/build.sh

@@ -34,9 +34,10 @@ docker run --rm --label=gulp \
 
 # -e HUGO_ENV=production : tell hugo to build a production-ready version of the site
 # ash -c "rm -rf..." : remove any old build artifacts and rebuild the site using the config matching the command line argument ($1)
+# chown 1001:1000 : make sure the resulting `release` directory is owned by gitlab-runner user
 docker run --rm --label=hugo \
     --volume=$(pwd):/src \
     --volume=$(pwd)/release:/tmp/build \
     -e HUGO_ENV=production \
     jojomi/hugo:0.40.2 \
-    ash -c "rm -rf /tmp/build/* && hugo --config config.toml,config-$1.toml --destination /tmp/build"
+    ash -c "rm -rf /tmp/build/* && hugo --config config.toml,config-$1.toml --destination /tmp/build && chown 1001:1001 /tmp/build -R"