use SERVER constant for setting the server address to localhost

cli/updater/updater.go

@@ -25,6 +25,8 @@ import (
 	"github.com/urfave/cli"
 )
 
+const SERVER = "localhost"
+
 var majorUpdate bool
 var majorFlag = &cli.BoolFlag{
 	Name:        "major, m",
@@ -330,8 +332,8 @@ func upgrade(cl *dockerclient.Client, stackName string, recipeName string, upgra
 	app := config.App{
 		Name:   stackName,
 		Recipe: recipeName,
-		Server: "localhost",
 		Env:    getEnv(cl, stackName),
+		Server: SERVER,
 	}
 
 	processRecipeRepoVersion(recipeName, upgradeVersion)