resolved npm cache clean error & created forgotten directory

Dockerfile

@@ -1,8 +1,7 @@
 FROM node:alpine
 COPY . /usr/src/app
 WORKDIR /usr/src/app
-RUN npm install && \
-    npm cache clean
+RUN npm install --no-cache
 EXPOSE 8080
 RUN chmod +x /usr/src/app/docker-entrypoint.sh
-ENTRYPOINT ["/usr/src/app/docker-entrypoint.sh", "npm", "start"]
+ENTRYPOINT ["/usr/src/app/docker-entrypoint.sh", "npm", "start"]

docker-entrypoint.sh

@@ -2,6 +2,7 @@
 
 set -e
 
+mkdir /usr/src/app/external-public/
 cp -R /usr/src/app/public/* /usr/src/app/external-public/
 
 exec "$@"