add files in package.json (#39)

Author: odanado

package.json

@@ -56,5 +56,10 @@
   "publishConfig": {
     "access": "public",
     "registry": "https://registry.npmjs.org/"
-  }
+  },
+  "files": [
+    "dist",
+    "README.md",
+    "LICENSE.txt"
+  ]
 }