Add "clean" script

mjackson · mjackson · commit 094718807abf · 2018-12-12T11:25:21.000-08:00
diff --git a/.gitignore b/.gitignore
@@ -1,2 +1,2 @@
-build
-node_modules
+/build/
+/node_modules/
diff --git a/.prettierignore b/.prettierignore
@@ -0,0 +1 @@
+package.json
diff --git a/package.json b/package.json
@@ -15,6 +15,7 @@
   "repository": "ReactTraining/react-stdio",
   "scripts": {
     "build": "./scripts/build.sh",
+    "clean": "git clean -fdX .",
     "test": "jest"
   },
   "dependencies": {
