Create external traffic path to the OpCode backend for Admin panel

[ohaiwalt]

From here: https://operation-code.slack.com/archives/C83BJQ4KX/p1522632151000002

Definition of done:

• Add DNS record in DNSimple for admin.operationcode.org CNAME to the Kubernetes cluster Ingress load balancer
• Create Ingress resource that directs traffic on admin.operationcode.org to the backend service
• Verify with backend team that traffic is reaching appropriately

[nellshamrell]

Turns out we already have this set up with api.operationcode.org :D Closing.