build: yarn build command

Author: terovirtanen

package.json

@@ -4,6 +4,7 @@
   "description": "Pulkka UI - A user interface for storing observations with timestamps",
   "main": "",
   "scripts": {
+    "build": "yarn dist",
     "clean": "rimraf dist/*",
     "copy": "copyfiles -f ./src/index.html ./src/pulkka.appcache ./dist && copyfiles -u 1 ./src/favicons/* ./src/img/* ./dist",
     "dist": "npm run copy & webpack --env=dist",