Update SDK page with full list of current SDKs. (#778)

Also made a better landing page for the Go SDK

site/content/en/docs/Guides/Client SDKs/_index.md

@@ -12,8 +12,11 @@ The client SDKs are required for a game server to work with Agones.
 
 The current supported SDKs are:
 
+- [Unreal Engine]({{< relref "unreal.md" >}})
 - [C++]({{< relref "cpp.md" >}})
-- [Go](https://godoc.org/agones.dev/agones/sdks/go)
+- [Node.js]({{< relref "nodejs.md" >}})
+- [Go]({{< relref "go.md" >}})
+- [Rust]({{< relref "rust.md" >}})
 - [REST]({{< relref "rest.md" >}})
 
 The SDKs are relatively thin wrappers around [gRPC](https://grpc.io) generated clients,

site/content/en/docs/Guides/Client SDKs/go.md

@@ -0,0 +1,17 @@
+---
+title: "Go Game Server Client SDK"
+linkTitle: "Go"
+date: 2019-05-17T10:17:50Z
+weight: 30
+description: "This is the Go version of the Agones Game Server Client SDK. "
+---
+
+Check the [Client SDK Documentation]({{< relref "_index.md" >}}) for more details on each of the SDK functions and how to run the SDK locally.
+
+## Installation
+
+`go get` the source, {{< ghlink href="sdks/go" >}}directly from Github{{< /ghlink >}}
+
+## Usage
+
+Review the [GoDoc](https://godoc.org/agones.dev/agones/sdks/go) for usage instructions