edited readme

README.md

@@ -47,7 +47,9 @@ We use https://www.npmjs.com/package/rc for configuration. This means config par
 locations command-line args or ENV variables. We recommend to use a file in current directory in INI or JSON format called ".spmagentrc".
 This file can be generated by calling a helper script:
 
-        node ./node_modules/spm-agent-nodejs/bin/spmconfig.js YOUR-NODEJS-MONITORING-TOKEN YOUR-INFRA-MONITORING-TOKEN
+        export MONITORING_TOKEN=YOUR-NODEJS-MONITORING-TOKEN
+        export INFRA_TOKEN=YOUR-INFRA-MONITORING-TOKEN
+        node ./node_modules/spm-agent-nodejs/bin/spmconfig.js
 
 The command above generates following default configuration file (YAML format):