Update README.md

README.md

 ansible_cluster_in_a_box
 ========================
+
+The aim of this repo is to provide a set or ansible roles that can be used to deploy a cluster
+We are working from 
+https://docs.google.com/a/monash.edu/spreadsheets/d/1IZNE7vMid_SHYxImGVtQcNUiUIrs_Nu1xqolyblr0AE/edit#gid=0
+as our architecture document.
+
+We aim to make these roles as generic as possible. You should be able to start from an inventory file, an ssh key and a git clone of this and end up with a working cluster. In the longer term we might branch to include utilities to make an inventory file using NeCTAR credentials.
+
+If you need a password use get_or_make_password.py (delegated to the passwword server/localhost) to generate a random one that can be shared between nodes
+
+We aim to make these roles run on all common linux platforms (both RedHat and Debian derived) but at the very least they should work on a CentOS 6 install.