Add build script to npm

package.json

@@ -3,7 +3,6 @@
   "version": "2.0.0",
   "description": "Your tabs, managed.",
   "dependencies": {
-    "legally": "^2.10.0",
     "twig": "^1.12.0"
   },
   "devDependencies": {
@@ -27,7 +26,7 @@
     "yargs": "^11.0.0"
   },
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "build": "npx gulp build"
   },
   "repository": {
     "type": "git",