Conform the use of docker images by implementing the use of environment variables for all options available to Docker images and start node on docker run automatically.

Dockerfile

@@ -8,7 +8,12 @@ RUN npm ci
 
 COPY . .
 
+# environment settings
+ENV NODE_ENV="production"
+
 EXPOSE 3000
 
 HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
   CMD wget --quiet --tries=1 --spider http://localhost:3000 || exit 1
+
+ENTRYPOINT ["node", "index.js"]