Right now our API schema is relatively flexible. We only define a single external version, v1alpha1, and we give no guarantees on the stability of this API.

Now that we're at a point where the project does function, we should review our schema to make sure it's consistent and makes sense. This specifically relates to the 'Issuer' and 'Certificate' resource type.

An example for ACME can be found here: https://github.com/jetstack-experimental/cert-manager/blob/master/docs/acme-cert.yaml and here: https://github.com/jetstack-experimental/cert-manager/blob/master/docs/acme-issuer.yaml. The full type definitions can be found in types.go.