add docs about container type
add docs about container type

dalehamel/minikube,dalehamel/minikube,warmchang/minikube,warmchang/minikube,kubernetes/minikube,warmchang/minikube,kubernetes/minikube,warmchang/minikube,warmchang/minikube,kubernetes/minikube,dalehamel/minikube,warmchang/minikube,kubernetes/minikube,kubernetes/minikube,warmchang/minikube,kubernetes/minikube,kubernetes/minikube