Prevent copying the jenkins war in two different layers
diff --git a/Dockerfile b/Dockerfile
index 7241039..0a79897 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,15 +6,15 @@
ENV JENKINS_VERSION 1.565.3
RUN mkdir /usr/share/jenkins/
RUN useradd -d /home/jenkins -m -s /bin/bash jenkins
-RUN curl -L http://mirrors.jenkins-ci.org/war-stable/$JENKINS_VERSION/jenkins.war -o /usr/share/jenkins/jenkins.war
+
+COPY init.groovy /tmp/WEB-INF/init.groovy
+RUN curl -L http://mirrors.jenkins-ci.org/war-stable/$JENKINS_VERSION/jenkins.war -o /usr/share/jenkins/jenkins.war \
+ && cd /tmp && zip -g /usr/share/jenkins/jenkins.war WEB-INF/init.groovy && rm -rf /tmp/WEB-INF
ENV JENKINS_HOME /var/jenkins_home
RUN usermod -m -d "$JENKINS_HOME" jenkins && chown -R jenkins "$JENKINS_HOME"
VOLUME /var/jenkins_home
-COPY init.groovy /tmp/WEB-INF/init.groovy
-RUN cd /tmp && zip -g /usr/share/jenkins/jenkins.war WEB-INF/init.groovy && rm -rf /tmp/WEB-INF
-
# define url prefix for running jenkins behind Apache (https://wiki.jenkins-ci.org/display/JENKINS/Running+Jenkins+behind+Apache)
ENV JENKINS_PREFIX /