added installation instructions

Author: kbouchard

README.md

@@ -2,3 +2,12 @@ Boris - Google Chrome extension
 ===============================
 
 Catch and redirect resources loaded from a specific domain / path.
+
+Installation
+---------------------
+1. To install the dev version, download or clone this repo.
+2. Navigate to *chrome://extensions* , then click on *Load unpacked extension...*
+3. Select *boris/* folder.
+4. Congratz!
+
+