Update README.md with new validation methods

Author: John Cordeiro

README.md

@@ -36,7 +36,7 @@ Latest Version: [![Latest version](https://jitpack.io/v/Ilhasoft/data-binding-va
 
 ## Sample
 
-<img width='380' src='https://raw.githubusercontent.com/Ilhasoft/data-binding-validator/master/screenshot.png'/>
+<img src="usageSample.gif" alt="...">
 
 ## Usage
 
@@ -164,6 +164,10 @@ You can add custom error messages by using the same validation rule name and add
   app:validateDateMessage="@{@string/dateErrorMessage}" />
 ```
 
+### Validating ###
+
+If you want to validate all the fields, you can simply call `validator.validate()`, to validate specific views you can call `validator.validate(view)` or `validator.validate(viewsList)`;
+
 ### Validation modes ###
 
 The validation can be applied in two way, field by field or the whole form at once. By default, it's configured field by field, however, you can call `validator.enableFormValidationMode();` to enable the validation of the whole form.