Enable multi-stage Docker build

This will allow to make the production container smaller.

Author: ForNeVeR

.dockerignore

@@ -0,0 +1,11 @@
+/.bsp/
+/.idea/
+/project/project/
+/project/target/
+
+/devenv
+/devenv.ps1
+/docker-compose.yml
+/*.dockerfile
+
+*/target/

loglist.dockerfile

@@ -1,4 +1,4 @@
-FROM hseeberger/scala-sbt:11.0.8_1.4.0_2.13.3
+FROM hseeberger/scala-sbt:11.0.8_1.4.0_2.13.3 as build
 
 WORKDIR /loglist
 COPY . .
@@ -7,13 +7,15 @@ RUN mkdir /opt/loglist
 RUN cp scalajvm/target/universal/scalajvm*zip /opt/loglist
 
 WORKDIR /opt/loglist
-# Steps below mirror our scripts/start.sh
 RUN unzip *.zip
 RUN mv scalajvm-*/* .
 RUN rm -rf scalajvm-*
-# Steps below mirror our docs/loglist.service
-# We don't set `-Dhttp.address=127.0.0.1` because we want the service to be
-# accessible from outside.
-ENTRYPOINT /opt/loglist/bin/scalajvm -Dhttp.port=9000 -Dpidfile.path=/dev/null
+
+FROM openjdk:11.0.9-jre
+
+WORKDIR /app
+COPY --from=build /opt/loglist .
+
+ENTRYPOINT /app/bin/scalajvm -Dhttp.port=9000 -Dpidfile.path=/dev/null
 
 EXPOSE 9000/tcp