Small improvements to the README

Very small improvements to the README.

#6 (closed)

README.md

-# ansible-roles
+# Shared Ansible roles
+
+This repository contains DevOps group shared ansible roles.
+
+## Best Practices
+All roles in this repository should:
+- Have a README
+- Have a usage example
+- Assert all required variables are set
+- Be idempotent
+- Be compose-able
+- Be orthogonal
+- Should pass ansible-lint checking
+
+
+