package: add cross-dev

Author: yihou

package.json

@@ -5,7 +5,7 @@
   "scripts": {
     "postinstall": "cp env.example.js env.js",
     "start": "webpack-dev-server --config webpack/dev.config.js --watch",
-    "build": "NODE_ENV=production webpack --config webpack/prod.config.js --progress --display-error-details --color",
+    "build": "cross-env NODE_ENV=production webpack --config webpack/prod.config.js --progress --display-error-details --color",
     "precommit": "eslint src"
   },
   "repository": {
@@ -42,6 +42,7 @@
     "babel-preset-env": "^1.6.0",
     "clean-webpack-plugin": "^0.1.16",
     "copy-webpack-plugin": "^4.0.1",
+    "cross-env": "^5.0.1",
     "css-loader": "^0.28.4",
     "eslint": "^4.2.0",
     "eslint-loader": "^1.9.0",