title: Form validation custom message in codeigniter?
body: <p>In codeigniter I have used codeigniter form validation library in many controller,</p>
  
  <p>ex: -  </p>
  
  <blockquote>
    <p>$this->form_validation->set_rules('rank', 'Rank', 'required');</p>
  </blockquote>
  
  <p>If form validation failed, Then it displays </p>
  
  <pre><code>         "The Rank field is required."
  </code></pre>
  
  <p>Here I want to display custom message,One method I can follow is </p>
  
  <blockquote>
    <p>$this->form_validation->set_message('required', '%s can not be blank');</p>
  </blockquote>
  
  <p>If I using this method then I need to repeat this code in every controller wherever I am using "required" form validation method</p>
  
  <p>My question is there is any method to declare  this  custom message in configure file and automatically use this custom message whenever I using form validation rule "required"?</p>