The only officialy supported method of installing this plugin is via composer.

Using Composer

View on Packagist, and copy the json snippet for the latest version into your project’s composer.json. Eg, v. 0.0.1 would look like this:

    "require": {
        "josegonzalez/cakephp-mail-preview": "0.0.1"

Enable plugin

You need to enable the plugin your config/bootstrap.php file:

Plugin::load('Josegonzalez/MailPreview', ['routes' => true]);

If you are already using Plugin::loadAll();, then this is not necessary.