title: Grails: custom constraint error messages
body: <p>I have class like this </p>
  
  <pre><code>class Account{
  
     AccType type ;
  
     static constraints ={
        type(nullable:false);
     }
  }
  </code></pre>
  
  <p>and in grails/i18n/message.properties I wrote:</p>
  
  <blockquote>
    <p>account.type.null = Please filled in with account type</p>
  </blockquote>
  
  <p>but it seems the error still : 
  Property [type] of class [class Account] cannot be null</p>
  
  <p>How to change the error messages with my own message.</p>