add plugin to devDependencies

Author: edeustace

package.json

@@ -11,7 +11,7 @@
     "prepublish": "npm run build",
     "build": "./node_modules/.bin/babel src -d lib",
     "it": "./node_modules/.bin/mocha --require babel-register test/integration/**",
-    "postinstall":  "./bin/postinstall"
+    "postinstall": "./bin/postinstall"
   },
   "repository": {
     "type": "git",
@@ -33,6 +33,7 @@
   "homepage": "https://github.com/PieLabs/pie-cli#readme",
   "devDependencies": {
     "babel-cli": "^6.14.0",
+    "babel-plugin-transform-es2015-modules-commonjs": "^6.16.0",
     "chai": "^3.5.0",
     "expand-home-dir": "0.0.3",
     "minimist": "^1.2.0",