chore(readme): update readme with firefox details

README.md

@@ -1,25 +1,37 @@
-chrome-extension
-================
+The Green Web chrome-extension
+==============================
 
 The Green Web Addon For Chrome
 
+Should also work on other browsers with web-extensions support like Firefox (48+), Opera and Edge (not tested)
+
 Usage
 =====
 
 Want to use this extension, install it from the chrome webstore : 
 
   https://chrome.google.com/webstore/detail/the-green-web/ekiibapogjgmlhlhpoalbppfhhgkcogc
+
+For firefox:
+  https://addons.mozilla.org/nl/firefox/addon/the-green-web/
 
 Want to help?
 =============
 
-Development
+Development on Chrome
   1. git clone [email protected]:thegreenwebfoundation/chrome-extension.git
   2. Open Chrome, click Extra -> Extensions and click on Developer Mode
   3. Use "Load unpacked extension" to load this directory
   4. Make your changes, test them out (use ctrl+r in the extension screen to reload)
   5. Happy with the changes? Do a commit and make a pull request
 
+Development on Firefox
+  1. git clone [email protected]:thegreenwebfoundation/chrome-extension.git
+  2. Install web-ext (npm install -g web-ext)
+  3. run web-ext run
+  4. Make your changes, test them out (use ctrl+r in the terminal where web-ext is running to reload)
+  5. Happy with the changes? Do a commit and make a pull request
+
 Found a bug?
 ============