install links for all browsers

README.md

@@ -8,7 +8,9 @@ Note: Activity from this Chrome extension will not display on leaderboards, so i
 
 1. Install the extension:
 
-[![Chrome Web Store](https://wakatime.com/static/img/chrome-web-store.png)](https://chrome.google.com/webstore/detail/wakatime/jnbbnacmeggbgdjgaoojpmhdlkkpblgi)
+[![Chrome](https://wakatime.com/static/img/chrome-web-store.png)](https://chrome.google.com/webstore/detail/wakatime/jnbbnacmeggbgdjgaoojpmhdlkkpblgi)
+[![Firefox](https://wakatime.com/static/img/firefox-addon.png)](https://addons.mozilla.org/en-US/firefox/addon/wakatimes/)
+[![Edge](https://wakatime.com/static/img/microsoft-extension.png)](https://microsoftedge.microsoft.com/addons/detail/wakatime/cdnpfnaadjmaplhghnlonephmabegadl)
 
 2. Login to [WakaTime](https://wakatime.com/).