[doc] VS Code IDE setup (ray-project#613)

VS Code setup for a project with multiple Go modules is tricky. Hence, this PR provides a workspace configuration for developers.

Signed-off-by: Kai-Hsun Chen <[email protected]>

kuberay.code-workspace

@@ -0,0 +1,20 @@
+{
+	"folders": [
+		{
+			"path": "."
+		},
+		{
+			"path": "ray-operator"
+		},
+		{
+			"path": "apiserver"
+		},
+		{
+			"path": "cli"
+		},
+		{
+			"path": "proto"
+		}
+	],
+	"settings": {}
+}

ray-operator/DEVELOPMENT.md

@@ -30,6 +30,13 @@ export PATH="$GOROOT/bin:$PATH"
 
 ## Development
 
+### IDE Setup (VS Code)
+* Step 1: Install the [VS Code Go extension](https://marketplace.visualstudio.com/items?itemName=golang.go).
+* Step 2: Import the KubeRay workspace configuration by using the file `kuberay.code-workspace` in the root of the KubeRay git repo:
+  * "File" -> "Open Workspace from File" -> "kuberay.code-workspace"
+
+Setting up workspace configuration is required because KubeRay contains multiple Go modules. See the [VS Code Go documentation](https://github.com/golang/vscode-go/blob/master/README.md#setting-up-your-workspace) for details.
+
 ### Build the source code
 
 ```