add version from flag

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

gorush/const.go

@@ -1,10 +1,5 @@
 package gorush
 
-const (
-	// Version is gorush server version.
-	Version = "1.2.1"
-)
-
 const (
 	// PlatFormIos constant is 1 for iOS
 	PlatFormIos = iota + 1

gorush/version.go

@@ -6,10 +6,16 @@ import (
 	"runtime"
 )
 
+var version string
+
+func SetVersion(ver string) {
+	version = ver
+}
+
 // PrintGoRushVersion provide print server engine
 func PrintGoRushVersion() {
 	fmt.Printf(`GoRush %s, Compiler: %s %s, Copyright (C) 2016 Bo-Yi Wu, Inc.`,
-		Version,
+		version,
 		runtime.Compiler,
 		runtime.Version())
 }
@@ -18,7 +24,7 @@ func PrintGoRushVersion() {
 func VersionMiddleware() gin.HandlerFunc {
 	// Set out header value for each response
 	return func(c *gin.Context) {
-		c.Writer.Header().Set("Server-Version", "GoRush/"+Version)
+		c.Writer.Header().Set("Server-Version", "GoRush/"+version)
 		c.Next()
 	}
 }