Add doc to run only one unit test

.github/CONTRIBUTING.md

@@ -146,3 +146,9 @@ Build the application and run the unit/integration tests:
 $ npm run build
 $ npm test
 ```
+
+If you just want to run 1 test:
+
+```
+$ npm run mocha -- --exit --require ts-node/register/type-check --bail server/tests/api/index.ts
+```

package.json

@@ -47,6 +47,7 @@
     "nodemon": "nodemon",
     "ts-node": "ts-node",
     "tslint": "tslint",
+    "mocha": "mocha",
     "travis": "scripty",
     "release": "scripty",
     "client-report": "scripty"