add english version

en/code/src/apps/ch.2.1/main.go

@@ -0,0 +1,11 @@
+// Example code for Chapter ? from "Build Web Application with Golang"
+// Purpose: Hello world example demonstrating UTF-8 support.
+// To run in the console, type `go run main.go`
+// You're missing language fonts, if you're seeing squares or question marks.
+package main
+
+import "fmt"
+
+func main() {
+    fmt.Printf("Hello, world or 你好，世界 or καλημ ́ρα κóσμ or こんにちは世界\n")
+}