Added docker (w/o frontend)

Dockerfile_app

@@ -0,0 +1,23 @@
+FROM openjdk:8-jdk-alpine
+
+RUN apk add gradle libpcap
+
+COPY ./ /app/
+
+WORKDIR /app/
+
+RUN gradle --no-daemon build
+
+RUN cp build/libs/packmate-*.jar app.jar
+
+ENV DB_USER ${PACKMATE_DB_USER:-packmate}
+ENV DB_PASSWORD ${PACKMATE_DB_PASSWORD:-packmate_secret_password}
+ENV DB_NAME ${PACKMATE_DB_DB:-packmate}
+#ENV IFACE ${PACKMATE_INTERFACE:-eth0}
+ENV LOCAL_IP ${PACKMATE_LOCAL_IP:-192.168.1.0}
+ENV WEB_LOGIN ${PACKMATE_WEB_LOGIN:-BinaryBears}
+ENV WEB_PASSWORD ${PACKMATE_WEB_PASSWORD:-123456}
+
+EXPOSE 65000:65000
+
+CMD ./start.sh