Add, user and group for security

Dockerfile

@@ -10,11 +10,17 @@ COPY next.config.js tsconfig.json ./
 COPY ./public ./public
 COPY ./src ./src
 
+RUN addgroup --system --gid 1001 nodejs
+RUN adduser --system --uid 1001 nextjs
+
+RUN chown -R nextjs:nodejs /app
+USER nextjs
+
 RUN yarn install --immutable
 RUN yarn run build
 
 EXPOSE 80
 EXPOSE 443
 EXPOSE 3000
 
-CMD ["yarn", "start"]
+CMD ["yarn", "start"]