Set hostname in dockerfile

Dockerfile

@@ -2,7 +2,6 @@
 FROM node:18-alpine AS base
 # Build: run ooni-sysadmin.git/scripts/docker-build from this directory
 
-
 # Install dependencies only when needed
 FROM base AS deps
 # Check https://github.com/nodejs/docker-node/tree/b4117f9333da4138b03a546ec926ef50a31506c3#nodealpine to understand why libc6-compat might be needed.
@@ -32,6 +31,10 @@ RUN adduser --system --uid 1001 nextjs
 COPY --from=builder /app/next.config.js ./
 COPY --from=builder /app/public ./public
 
+# Set the correct permission for prerender cache
+RUN mkdir .next
+RUN chown nextjs:nodejs .next
+
 # Automatically leverage output traces to reduce image size
 # https://nextjs.org/docs/advanced-features/output-file-tracing
 COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
@@ -41,5 +44,9 @@ USER nextjs
 
 EXPOSE 3100
 ENV PORT 3100
+# set hostname to localhost
+ENV HOSTNAME "0.0.0.0"
 
+# server.js is created by next build from the standalone output
+# https://nextjs.org/docs/pages/api-reference/next-config-js/output
 CMD ["node", "server.js"]