Merge pull request #148 from henrikuittinen/patch-1

Use Docker multistage build to reduce image size

Dockerfile

@@ -1,6 +1,10 @@
-FROM node:8
+FROM node:8 as builder
 WORKDIR /workspace
 COPY . .
 RUN npm install
+
+FROM node:8-alpine
+WORKDIR /workspace
+COPY --from=builder /workspace .
 CMD npm start
 EXPOSE 3002