title: Not able to connect PostgreSQL with Yii
body: <p>I have tried to connect PostgreSQL with Yii but is is showing </p>
  
  <p>CDbConnection failed to open the DB connection.</p>
  
  <p>In log it is showing </p>
  
  <pre><code>error   exception.CDbException  
  </code></pre>
  
  <p>could not find driver</p>
  
  <p>My code</p>
  
  <pre><code>'db'=&gt;array(
      'tablePrefix'=&gt;'',
      'connectionString' =&gt; 'pgsql:host=localhost;port=5432;dbname=postgres',
      'username'=&gt;'postgres',
      'password'=&gt;'postgres',
      'charset'=&gt;'UTF8',
  ),
  </code></pre>