message: Update Dockerfile
  improving docker file performance
diff: FROM node:10-stretch
  -MAINTAINER Patrik J. Braun
  +LABEL maintainer="Patrik J. Braun"
  RUN git clone https://github.com/bpatrik/pigallery2.git && \
  cd /pigallery2 && \
  npm install --unsafe-perm && \
  - npm run build-release
  -
  -RUN cp -r /pigallery2/release /pigallery2-release && \
  - rm /pigallery2 -R
  -
  -RUN cd /pigallery2-release && \
  + npm run build-release && \
  + cp -r /pigallery2/release /pigallery2-release && \
  + rm /pigallery2 -R && \
  + cd /pigallery2-release && \
  npm install --unsafe-perm
  -cmd cd /pigallery2-release && npm start
  -
  +CMD cd /pigallery2-release && npm start
  