title: Read works, add, edit, delete do not in Grocery Crud library Codeigniter
body: <p>I have done the example and installed everything.</p>
  
  <p>The read or display method of table works correctly, but whenever I try to add, delete or edit a registry a windows appears and say:</p>
  
  <pre><code>404 Page Not Found
  
  The page you requested was not found.
  </code></pre>
  
  <p>Here is my Controller</p>
  
  <pre><code>class Welcome extends CI_Controller {
  
      public function __construct()
      {
          parent::__construct();
          $this-&gt;load-&gt;model('grocery_CRUD_model');
          $this-&gt;load-&gt;database();
          $this-&gt;load-&gt;helper('url');
          $this-&gt;load-&gt;library('grocery_CRUD');
      }
  
  
      public function index()
      {
          $crud = new grocery_CRUD();
  
          $crud-&gt;set_theme('datatables');
          $crud-&gt;set_table('students');
          $crud-&gt;set_relation('class','class','class');
          $crud-&gt;display_as('name','Name of Student');
          $crud-&gt;set_subject('Students');
          $crud-&gt;columns('name','class','roll_no');
          $crud-&gt;add_fields('name','class','roll_no');
          $crud-&gt;required_fields('name','class','roll_no');
          $crud-&gt;unset_export();
          $crud-&gt;unset_print();
          $output = $crud-&gt;render();
          $this-&gt;load-&gt;view('home', $output);
  
      }
  
  }
  </code></pre>
  
  <p>when i click ADD button URL becomes</p>
  
  <pre><code>http://localhost/index.php/add
  </code></pre>
  
  <p><strong>what is missed?
  i am new in codeigniter and Grocery Crud...</strong></p>