title: Multiple select box value does not inserting in codeigniter
body: <p>I tried to upload multiple select box value in my database using codeigniter but unable to do so. Every time i insert the value it just inserting one value.</p>
  
  <p><strong>view:</strong></p>
  
  <pre><code>&lt;?php echo form_open('admin/Doctors_controller/add') ?&gt;
      &lt;select class="form-control" name="timings[]" multiple&gt;
        &lt;option value="1"&gt;Apple&lt;/option&gt;
        &lt;option value="2"&gt;Mango&lt;/option&gt;
        &lt;option value="3"&gt;Blackberry&lt;/option&gt;
      &lt;/select&gt;
  &lt;?php echo form_close() ?&gt;
  </code></pre>
  
  <p><strong>Controller</strong></p>
  
  <pre><code>public function add(){
     $this-&gt;form_validation-&gt;set_rules('timings[]','timings','required');
  
     if ($this-&gt;form_validation-&gt;run() == FALSE){
          $this-&gt;session-&gt;set_flashdata('no','Doctor Could not be added');
          redirect('dashboards/doctor');
        }
        else{
          $this-&gt;Doctors_model-&gt;add_doc();
          $this-&gt;session-&gt;set_flashdata('yes','Doctor has been added');
          redirect('dashboards/doctor');
        }
  }
  </code></pre>
  
  <p><strong>Model</strong></p>
  
  <pre><code>public function add_doc(){
        $data = array(
           'timings' =&gt;implode(",", $this-&gt;input-&gt;post('timings[]'))
        );
        return  $this-&gt;db-&gt;insert('doctors',$data);
   }
  </code></pre>
  
  <p><strong>UPDATE</strong>
   <em>When i changed the database field type to varchar then it is submitting properly</em> </p>
  
  <p>By using this code i only able to insert one select box value .</p>