🌱 Add basic readme (#7)

Adding readme that explains the basic components and functionality of
the operator and gives references to related projects

Signed-off-by: janiskemper <[email protected]>

README.md

@@ -1 +1,25 @@
-# SCS Cluster Stack Operator
+# Cluster Stack Operator
+
+## Get started
+
+The Cluster Stack Operator works with [Cluster Stacks](https://github.com/SovereignCloudStack/cluster-stacks) and creates Kubernetes clusters in an easy and [Cluster-API](https://github.com/kubernetes-sigs/cluster-api)-native way.
+
+The operator can be used with any repository that contains releases of cluster stacks. For more details of how to implement them, have a look at the [cluster-stacks repository](https://github.com/SovereignCloudStack/cluster-stacks).
+
+To try out this operator and cluster stacks, have a look at this [demo](https://github.com/SovereignCloudStack/cluster-stacks-demo).
+
+## What is the Cluster Stack Operator?
+
+The Cluster Stack Operator facilitates the manual work that needs to be done to use cluster stacks. 
+
+There are three components of a cluster stack:
+
+1. Cluster addons: The cluster addons (CNI, CSI, CCM) have to be applied in each workload cluster that the user starts
+2. Cluster API objects: The `ClusterClass` object makes it easier to use Cluster-API. The cluster stack contains a `ClusterClass` object and other Cluster-API objects that are necessary in order to use the `ClusterClass`. These objects have to be applied in the management cluster.
+3. Node images: Node images can be provided to the user in different form. They are released and tested together with the other two components of the cluster stack.
+
+The first two are handled by this operator here. The node images, on the other hand, have to be handled by separate provider integrations, similar to the ones that [Cluster-API uses](https://cluster-api.sigs.k8s.io/developer/providers/implementers-guide/overview).
+
+## Implementing a provider integration
+
+Further information and documentation on how to implement a provider integration will follow soon.