Updated README.md to include CoreOS toolbox information
Updated README.md to include CoreOS toolbox information

kubernetes/minikube,r2d4/minikube,aaron-prindle/minikube,dalehamel/minikube,dalehamel/minikube,dlorenc/minikube,dongsupark/minikube,dlorenc/minikube,dlorenc/minikube,cu12/minikube,skipjaq/minikube,endocode/minikube,kubernetes/minikube,skipjaq/minikube,abbytiz/minikube,kubernetes/minikube,cu12/minikube,dongsupark/minikube,kubernetes/minikube,warmchang/minikube,dims/minikube,endocode/minikube,dalehamel/minikube,warmchang/minikube,dlorenc/minikube,warmchang/minikube,dongsupark/minikube,warmchang/minikube,dlorenc/minikube,abbytiz/minikube,r2d4/minikube,cu12/minikube,endocode/minikube,dlorenc/minikube,r2d4/minikube,kubernetes/minikube,kubernetes/minikube,warmchang/minikube,abbytiz/minikube,aaron-prindle/minikube,dims/minikube,kubernetes/minikube,skipjaq/minikube,warmchang/minikube,mikegrass/minikube,mikegrass/minikube,dlorenc/minikube,mikegrass/minikube,dims/minikube,dlorenc/minikube,aaron-prindle/minikube,warmchang/minikube