Added a build discard and branch name to tag.

jenkinsfile

@@ -1,6 +1,9 @@
 // Powered by Infostretch 
 pipeline{
     agent any
+    options {
+        buildDiscarder(logRotator(numToKeepStr: '30'))
+    }
     triggers {
         pollSCM('H/15 * * * *')
     }
@@ -14,9 +17,9 @@ pipeline{
     	    steps{
      			// Shell build step
                 sh """ 
-                docker build . -t $DOCKER_REGISTRY/$DOCKER_USER/$JOB_NAME --pull
+                docker build . -t $DOCKER_REGISTRY/$DOCKER_USER/$JOB_NAME:$BRANCH_NAME --pull
                 docker login $DOCKER_REGISTRY/$DOCKER_USER -u $DOCKER_USER -p $DOCKER_PASSWORD
-                docker push $DOCKER_REGISTRY/$DOCKER_USER/$JOB_NAME
+                docker push $DOCKER_REGISTRY/$DOCKER_USER/$JOB_NAME:$BRANCH_NAME
                 """ 
     	    }
     	}