[ONOS-3536] Implement back-end metrics saving logic using RRD

Change-Id: I1b3c495380884571dc88d2f9fb3152fdf41ef655
diff --git a/apps/cpman/app/pom.xml b/apps/cpman/app/pom.xml
index b7c76ae..78d88bf 100644
--- a/apps/cpman/app/pom.xml
+++ b/apps/cpman/app/pom.xml
@@ -105,6 +105,11 @@
             <version>1.1.1</version>
         </dependency>
         <dependency>
+            <groupId>org.rrd4j</groupId>
+            <artifactId>rrd4j</artifactId>
+            <version>2.2</version>
+        </dependency>
+        <dependency>
             <groupId>com.sun.jersey</groupId>
             <artifactId>jersey-servlet</artifactId>
         </dependency>