ci: add test for websocket

vendor/github.com/gorilla/websocket/examples/echo/README.md

@@ -0,0 +1,17 @@
+# Client and server example
+
+This example shows a simple client and server.
+
+The server echoes messages sent to it. The client sends a message every second
+and prints all messages received.
+
+To run the example, start the server:
+
+    $ go run server.go
+
+Next, start the client:
+
+    $ go run client.go
+
+The server includes a simple web client. To use the client, open
+http://127.0.0.1:8080 in the browser and follow the instructions on the page.