Merge pull request coreos#664 from joshix/regauthpointer

os/adding-CAs: Add links to auth'd registry doc.

os/adding-certificate-authorities.md

@@ -4,7 +4,7 @@ CoreOS supports custom Certificate Authorities (CAs) in addition to the default
 
 - Use a corporate wildcard certificate
 - Use your own CA to communicate with an installation of CoreUpdate
-- Use your own CA to communicate with a private Docker registry
+- Use your own CA to [encrypt communications with a container registry](registry-authentication.md)
 
 The setup process for any of these use-cases is the same:
 
@@ -14,5 +14,8 @@ The setup process for any of these use-cases is the same:
 
 ## More Information
 
-[Generate Self Signed Certificates](generate-self-signed-certificates.md)
+[Generate Self-Signed Certificates](generate-self-signed-certificates.md)
+
+[Use an insecure registry behind a firewall](registry-authentication.md#using-a-registry-without-ssl-configured)
+
 [etcd Security Model]({{site.baseurl}}/etcd/docs/latest/security.html)