Add missing rimraf dep

Author: exogen

package.json

@@ -48,6 +48,7 @@
     "doctoc": "^1.2.0",
     "nodemon": "^1.8.1",
     "pre-commit": "^1.1.3",
+    "rimraf": "^2.5.4",
     "snazzy": "^5.0.0",
     "standard": "^8.0.0"
   },