change Docker build strategy

Dockerfile

-FROM maven:3.3.9-jdk-8-onbuild
-VOLUME /var/lib/jetty/webapps
-CMD cp /usr/src/app/elevator-server/target/*.war /var/lib/jetty/webapps/root.war
+FROM maven:3.3.9-jdk-8-onbuild as install
+
+FROM jetty:9.3.11-jre8 as run
+COPY --from=install /usr/src/app/elevator-server/target/*.war /var/lib/jetty/webapps/root.war
\ No newline at end of file

run.sh

 #!/usr/bin/env bash
 
-docker run --name code-elevator-container code-elevator
-docker run --detach --publish 8080:8080 --volumes-from code-elevator-container jetty:9.3.11-jre8
+docker run --rm --detach --publish 8080:8080 code-elevator