Currently, we can fetch a consumer using it's username or ID.
Add a method to fetch a consumer using custom_id.

I'd like to build out the capabilities of this library to support Enterprise Edition entities. This would cover general CRUD operations around:

• Workspaces
• Workspace entities
• Users
• Admins
• Roles
• Endpoint permissions
• Entity permissions

This work is intended as a port of work completed here: kevholditch/gokong#74 with the goal of eventual implementation in a Kong Terraform provider, as well as decK.

• client_certificate property in Service resource
• headers property in Route resource
• New ca_certificate resource

healthchecks.active.unhealthy.interval is missing from the upstream definition.
Also, ensure that all the properties are covered and there is not another one that is missing.

Entities can be validated using /schemas/:entity_name/validate endpoint.

We are using go-kong and have been writing unit tests around our code. To help with this we have written interfaces for the various Services (RouteService, Svcservice, UpstreamService, and TargetService thus far).

In a way we have painted ourselves into a corner with this.

In trying to hook up the actual go-kong library we are writing super thin wrappers that meet our interface definitions and adapt to go-kong.

It would be much easier if the interfaces existed in go-kong.

Does this sound reasonable? We can prepare a PR if it something people think would be helpful.