New image tagging work in progress

Jenkinsfile

@@ -41,7 +41,7 @@ pipeline {
         sh "docker build --build-arg repo=${repo} --no-cache -t ${DOCKER_REGISTRY}/iru/${DOCKER_IMAGE}:${repo}-${BUILD_NUMBER} ."
         script {
            NEWTAG = sh script: "docker run --rm ${DOCKER_REGISTRY}/iru/${DOCKER_IMAGE}:${repo}-${BUILD_NUMBER} rpm -q --qf %{VERSION}-%{RELEASE} web-registry-admin 2> /dev/null", returnStdout: true
-           NEWTAG = NEWTAG + BUILD_NUMBER
+           NEWTAG = NEWTAG + "_" + BUILD_NUMBER
            echo "NEWTAG is $NEWTAG"
         }
       }