add options

src/manifest.json

@@ -14,9 +14,15 @@
     }
   },
   "background": {
-    "scripts": ["bg.js"]
+    "scripts": ["bg.js", "utils.js"]
   },
   "permissions": [
+    "storage",
+    "sessions",
     "<all_urls>"
-  ]
+  ],
+  "options_ui": {
+    "browser_style": true,
+    "page": "options/options.html"
+  }
 }