websocket: send dummy data in example configuration

etc/websocket.conf

@@ -46,12 +46,21 @@ nodes = {
 			{ label = "Rect",        unit = "Var"},
 			{ label = "Ramp",        unit = "°C" }
 		)
-	}
+	},
+  sig = {
+    type = "signal",
+
+    signal = "sine",
+    values = 1,
+    frequency = 50,
+
+    rate = 800
+  },
 };
 
 
 ############       List of paths       ############
 
 paths = (
-	{ in = "ws", out = "ws" }
+	{ in = "sig", out = "ws" }
 );