diff --git a/Dockerfile b/Dockerfile
index a4e4ec4..ed7ec74 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,23 +5,29 @@
 ENV JENKINS_VERSION 1.565.3
 ENV JENKINS_HOME /var/jenkins_home
 
-# `/usr/share/jenkins/ref/` contains all reference configuraiton we want to set on a fresh new installation
-# use it to bundle additional plugins or config file with your custom jenkins Docker image.
-RUN mkdir -p /usr/share/jenkins/ref/init.groovy.d
-
 # Jenkins is ran with user `jenkins`, uid = 1000
 # If you bind mount a volume from host/vloume from a data container, 
 # ensure you use same uid
 RUN useradd -d "$JENKINS_HOME" -u 1000 -m -s /bin/bash jenkins
 
+# Jenkins home directoy is a volume, so configuration and build history 
+# can be persisted and survive image upgrades
+VOLUME /var/jenkins_home
+
+# `/usr/share/jenkins/ref/` contains all reference configuration we want 
+# to set on a fresh new installation. Use it to bundle additional plugins 
+# or config file with your custom jenkins Docker image.
+RUN mkdir -p /usr/share/jenkins/ref/init.groovy.d
+
+
 COPY init.groovy /usr/share/jenkins/ref/init.groovy.d/tcp-slave-angent-port.groovy
 
-# could use ADD but this one does not check Last-Modified header - see https://github.com/docker/docker/issues/8331
+# could use ADD but this one does not check Last-Modified header 
+# see https://github.com/docker/docker/issues/8331
 RUN curl -L http://mirrors.jenkins-ci.org/war-stable/$JENKINS_VERSION/jenkins.war -o /usr/share/jenkins/jenkins.war
 
 ENV JENKINS_UC https://updates.jenkins-ci.org
 RUN chown -R jenkins "$JENKINS_HOME" /usr/share/jenkins/ref
-VOLUME /var/jenkins_home
 
 # for main web interface:
 EXPOSE 8080