title: How I Creat TIMESTAMP field while migration in CODEIGNITER with CURRENT_TIME on update
body: <p>Below is my code please tell me where i m wrong.. </p>
  
  <pre><code>public function up(){
  
          $this-&gt;dbforge-&gt;add_field(array(
                  'id'=&gt; array(
                      'type'          =&gt; 'int',
                      'constraint'    =&gt; 11,
                      'auto_increment'=&gt; TRUE,
                  ),
                  'ip_address'=&gt; array(
                      'type'      =&gt; 'VARCHAR',
                      'constraint'=&gt; '40',
                  ),
                  'login'=&gt; array(
                      'type'      =&gt; 'VARCHAR',
                      'constraint'=&gt; '50',
                  ),
                  'time'=&gt; array(
                      'type'      =&gt; 'timestamp',
                      'Default' =&gt; 'CURRENT_TIMESTAMP',
                      'ON UPDATE CURRENT_TIMESTAMP' =&gt; TRUE,
                  ),
          ));
          $this-&gt;dbforge-&gt;add_key('id',TRUE);
          $this-&gt;dbforge-&gt;create_table('login_attempts');
      echo "table created";       
      }
  </code></pre>
  
  <p>and this error will generate on running migration</p>
  
  <blockquote>
    <p>Error Number: </p>
    
    <p>1067</p>
    
    <p>Invalid default value for 'time'</p>
    
    <p>CREATE TABLE login_attempts ( id int(11) NOT NULL AUTO_INCREMENT,
    ip_address VARCHAR(40) NOT NULL, login VARCHAR(50) NOT NULL, time
    timestamp NOT NULL DEFAULT 'CURRENT_TIMESTAMP', CONSTRAINT
    pk_login_attempts PRIMARY KEY(id) ) DEFAULT CHARACTER SET = utf8
    COLLATE = utf8_general_ci</p>
    
    <p>Filename: D:/xampp/htdocs/tank_auth/system/database/DB_driver.php</p>
    
    <p>Line Number: 691</p>
  </blockquote>