Add a few badges (#50)

#6 

README.md

 # postgres operator
 
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 The Postgres operator manages Postgres clusters in Kubernetes using the [operator pattern](https://coreos.com/blog/introducing-operators.html).
 During the initial run it registers the [Third Party Resource (TPR)](https://kubernetes.io/docs/user-guide/thirdpartyresources/) for Postgres.
 The Postgresql TPR is essentially the schema that describes the contents of the manifests for deploying individual Postgres clusters using Statefulsets and Patroni.