title: get custom field value using Grocery CRUD CodeIgniter
body: <p>How can i get value of a field from another table on my method? and of course i have the primary key of its table.
  i want to do something in add/edit action like this</p>
  
  <pre><code>if(is_empty(value_field_from_another_table)){
      $crud-&gt;edit_fields('first','second');
      $crud-&gt;add_fields('first','second');
  }else{
      $crud-&gt;edit_fields('first');
      $crud-&gt;add_fields('first');
  }
  </code></pre>