add prepublish script back in

Author: Charlie Kassel

package.json

@@ -25,7 +25,8 @@
     "build": "rm -rf dist && node build/build.js",
     "unit": "cross-env BABEL_ENV=test karma start test/unit/karma.conf.js --single-run",
     "test": "npm run unit",
-    "lint": "eslint --ext .js,.vue src test/unit/specs"
+    "lint": "eslint --ext .js,.vue src test/unit/specs",
+    "prepublish": "npm run build"
   },
   "dependencies": {
     "babel-runtime": "^6.0.0"