Support default redis address

example_test.go

@@ -24,7 +24,7 @@ func init() {
 
 func ExampleNewClient() {
 	redisdb := redis.NewClient(&redis.Options{
-		Addr:     "localhost:6379",
+		Addr:     "localhost:6379", // use default Addr
 		Password: "",               // no password set
 		DB:       0,                // use default DB
 	})

options.go

@@ -101,6 +101,9 @@ func (opt *Options) init() {
 	if opt.Network == "" {
 		opt.Network = "tcp"
 	}
+	if opt.Addr == "" {
+		opt.Addr = "localhost:6379"
+	}
 	if opt.Dialer == nil {
 		opt.Dialer = func() (net.Conn, error) {
 			netDialer := &net.Dialer{