add api/cli for assigning user a role with experiment

bin/dm-add-user-experiment-role

+#!/bin/sh
+
+# Run command
+
+if [ -z $DM_ROOT_DIR ]; then
+    cd `dirname $0` && myDir=`pwd`
+    setupFile=$myDir/../setup.sh
+    if [ ! -f $setupFile ]; then
+        echo "Cannot find setup file: $setupFile"
+        exit 1
+    fi
+    source $setupFile > /dev/null
+fi
+
+$DM_ROOT_DIR/src/python/dm/ds_web_service/cli/addUserExperimentRoleCli.py $@
+
+