fixed examples in readme

Author: christianmueller-ambifox

README.md

@@ -5,6 +5,7 @@ You have to call it´s GetSecret() method to get the actual value.
 
 It is highly inspired by Pydantic´s SecretStr (https://docs.pydantic.dev/usage/types/#secret-types)
 
+Example usage:
 ```go
 package main
 
@@ -14,20 +15,43 @@ import (
 )
 
 func main() {
-	s := secretstring.SecretString("this_is_a_secret")
-	// or
-	// var s SecretString = "this_is_a_secret"
+	// create a new secret string with default options
+	s := secretstring.New("this_is_a_secret")
 
 	fmt.Println(s)
 	fmt.Println(s.GetSecret())
+	
+	// output:
+	// **********
+	// this_is_a_secret
 }
 ```
 
-this should output:
+Or with custom options:
 
-```
-********
-this_is_a_secret
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/chmller/secretstring"
+)
+
+func main() {
+	// create a new secret string with custom options
+	o := secretstring.Options{
+		MarshallMasked: false,
+		Mask: "???",
+    }
+	s := secretstring.NewWithOptions("this_is_a_secret", o)
+
+	fmt.Println(s)
+	fmt.Println(s.GetSecret())
+
+	// output:
+	// ???
+	// this_is_a_secret
+}
 ```
 
 It has build in marshaller and unmarshaller for JSON.