add debugging info to contributing.md

CONTRIBUTING.md

@@ -14,13 +14,23 @@
 
 ## Running tests
 
-* `ember test` – Runs the test suite on the current Ember version
-* `ember test --server` – Runs the test suite in "watch mode"
-* `ember try:each` – Runs the test suite against multiple Ember versions
+* `npm run test:node` - Runs the node tests, which verify memory leak detection behavior.
+* `ember test` – Runs the dummy app test suite on the current Ember version. Will fail with a memory leak detection.
+* `ember test --server` – Runs the dummy app test suite in "watch mode"
+* `ember try:each` – Runs the dummy app test suite against multiple Ember versions
 
 ## Running the dummy application
 
 * `ember serve`
 * Visit the dummy application at [http://localhost:4200](http://localhost:4200).
 
 For more information on using ember-cli, visit [https://ember-cli.com/](https://ember-cli.com/).
+
+## Debugging
+
+Since most of this addon's functionality takes place in node, it can be helpful to run commands with a node debugger enabled. 
+
+1. Place a debugger anywhere in the `lib` directory js files.
+1. Visit `chrome://inspect` in Chrome
+1. Click `Open dedicated DevTools for Node`
+1. Run `node --inspect node_modules/.bin/ember test`, for example, to run the dummy app tests and stop on the debugger once memory leak detection runs.