title: zend framework custom validation classes
body: <p>I'm writing a custom validator that is going to check for the existence of an email such that if it already exists in the database, the form is not valid. I'm having a hard time figuring out helper paths and namespaces for custom Zend_Validation classes.</p>
  
  <p>I'd like to call the class My_Validate_EmailUnique but I keep getting error messages such as:
  there is an error exception 'Zend_Loader_PluginLoader_Exception' with message 'Plugin by name 'My_Validate_EmailUnique' was not found in the registry; used paths: My_Validate_: /var/www/site/arc/helpers/</p>
  
  <p>The class looks like this:</p>
  
  <pre><code>    &lt;?php
  class My_Validate_EmailUnique extends Zend_Validate_Abstract
  {
      const EMAIL_UNIQUE = 'notMatch';
  </code></pre>
  
  <p>Can someone help me with where I register for the Zend_Form to look for custom validators?</p>