init maven subsystem in docker

build/Dockerfile

@@ -9,6 +9,11 @@ COPY target/mavor.war /usr/local/tomcat/webapps/ROOT.war
 # create temporary directory, no need to be a volume
 RUN mkdir /mavor
 
+# this mvn command fails but is intended to fail
+# it just initializes maven subsystem so the first
+# download on the website is faster
+RUN /usr/bin/mvn dependency:copy-dependencies || echo "maven init done. fail is intended"
+
 # set required ENV
 ENV MAVOR_MAVEN_EXECUTABLE="/usr/bin/mvn"
 ENV MAVOR_TEMP_DIR="/mavor"