Add docker tasks to gradle

server/Dockerfile

@@ -0,0 +1,10 @@
+FROM openjdk:8-jre-alpine
+RUN mkdir /app
+COPY uhabits-server.jar /app/uhabits-server.jar
+WORKDIR /app
+CMD ["java", \
+     "-server", \
+     "-XX:MaxGCPauseMillis=100", \
+     "-XX:+UseStringDeduplication", \
+     "-jar", \
+     "uhabits-server.jar"]