Update README.md

README.md

@@ -2,9 +2,13 @@
 
 This is Kippt.com's official Firefox add-on. It's licensed under MIT and we'll accept improvements in pull-requests.
 
+The extension was build using [Firefox Add-on SDK](https://addons.mozilla.org/en-US/developers/docs/sdk/1.0/dev-guide/addon-development/about.html) and you can compile it with the following command:
+
+    cfx xpi
+
 Originally created by @thierrylemoulec
 
 ## TODO
 
-* Icon in right size
-* Add keyboard shortcut (e.g. cmd+shift+k)
+* Add keyboard shortcut (e.g. cmd+shift+k)
+* Add context menu