message: ledger: add link to Firefox version
diff: @@ -14,7 +14,7 @@ Adds some nice options on [TweetDeck](http://tweetdeck.twitter.com) to provide a
  The extensions is currently available for the following browsers:
  - [Chrome](https://chrome.google.com/webstore/detail/bettertweetdeck-3/micblkellenpbfapmcpcfhcoeohhnpob)
  - [Opera](https://addons.opera.com/en/extensions/details/bettertweetdeck/)
  -- ~~Firefox~~ SOON
  +- [Firefox](https://addons.mozilla.org/en-US/firefox/addon/better-tweetdeck-17/)
  # Features
  