Update README.md

README.md

@@ -23,7 +23,7 @@
 NodeBB requires the following software to be installed:
 
 * A version of Node.js at least 0.8 or greater
-* Redis, version 2.6 or greater.
+* Redis, version 2.6 or greater or MongoDB, version 2.4 or greater
 * nginx, version 1.3.13 or greater (**only if** intending to use nginx to proxy requests to a NodeBB)
 
 ## Installation
@@ -32,6 +32,8 @@ First, we install our base software stack:
 
 	# apt-get install git nodejs redis-server npm build-essential imagemagick
 
+If you want to use MongoDB instead of Redis install it from http://www.mongodb.org/downloads and remove 'redis-server' from the above command.
+
 **If your package manager only installed a version of Node.js that is less than 0.8 (e.g. Ubuntu 12.10, 13.04):**
 
 	# add-apt-repository ppa:chris-lea/node.js