Updated README

Added info on how to develop

README.md

@@ -7,3 +7,13 @@ glad to accept a pull that abstracts out the NaCL-specific stuff to optionally
 use a JS implementation for FF.
 Note that the code is currently quite messy (its all in one file!), but it
 needs to work first, then it can be heavily cleaned up later.
+
+Developing
+===========
+
+# Clone the repo
+# Open Chrome
+# Go to chrome://extensions/
+# Enable developer mode (checkbox on the top right)
+# Click "Load unpacked extension..."
+# Point to the repo's directory