feat: Firefox Support (#33)

* fix(storage): Make storage work on Firefox by setting a addon id (see https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/browser_specific_settings#Firefox_(Gecko)_propertiesfor context)

* fix(fetch): Add api.github.com to permissions array so addon can request data from there in Firefox

src/manifest.json

@@ -10,6 +10,7 @@
   },
   "permissions": [
     "https://github.com/*/*",
+    "https://api.github.com/*",
     "storage",
     "identity"
   ],
@@ -41,5 +42,10 @@
   "options_ui": {
     "page": "options.html",
     "chrome_style": true
+  },
+  "applications": {
+    "gecko": {
+      "id": "contributors-on-github@hzoo.github.com"
+    }
   }
 }