interface implement type check (#1459)

interface implement type check

render/render.go

@@ -26,6 +26,7 @@ var (
 	_ Render     = YAML{}
 	_ Render     = MsgPack{}
 	_ Render     = Reader{}
+	_ Render     = AsciiJSON{}
 )
 
 func writeContentType(w http.ResponseWriter, value []string) {