Add instructions for KindleGen

readme.md

@@ -35,3 +35,10 @@ Calibre Web is a Python web app providing a clean interface for browsing, readin
 ## Requirements
 
 Python 2.7+
+     
+Optionally, to enable on-the-fly conversion from EPUB to MOBI when using the send-to-kindle feature:     
+
+1. Create a `vendor` folder in the app root
+2. [Download](http://www.amazon.com/gp/feature.html?docId=1000765211) Amazon's KindleGen tool for your platform and place the binary named as `kindlegen` in this folder. 
+
+Calibre Web supports on-the-fly conversion of EPUB ebooks to Kindle format. To enable this feature, download http://www.amazon.com/gp/feature.html?docId=1000765211