Update deps; improve build

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:10-alpine
+FROM node:12-alpine
 
 ENV PSITRANSFER_UPLOAD_DIR=/data \
     NODE_ENV=production
@@ -7,27 +7,26 @@ MAINTAINER Christoph Wiechert <wio@psitrax.de>
 
 WORKDIR /app
 
-ADD *.js package.json README.md /app/
+ADD *.js package.json package-lock.json README.md /app/
 ADD lib /app/lib
 ADD app /app/app
 ADD public /app/public
 
 # Rebuild the frontend apps
 RUN cd app && \
-    NODE_ENV=dev npm install --quiet 1>/dev/null && \
-    npm run build && \
-    cd .. && rm -rf app
-
-# Install backend dependencies
-RUN mkdir /data && \
+    NODE_ENV=dev npm ci && \
+    npm run build -- --no-info && \
+    cd .. && \
+    mkdir /data && \
     chown node /data && \
-    npm install --quiet 1>/dev/null
+    npm ci && \
+    rm -rf app
 
 EXPOSE 3000
 VOLUME ["/data"]
 
 USER node
 
-HEALTHCHECK CMD wget -O /dev/null -q http://localhost:3000
+# HEALTHCHECK CMD wget -O /dev/null -q http://localhost:3000
 
 CMD ["node", "app.js"]