"require": {
        "crabstudio/cakephp-sluggable": "dev-master"
    }

        $this->addBehavior('Crabstudio/Sluggable.Sluggable', [
            'field' => 'title',
            'slug' => 'slug',
            'replacement' => '-', 
            'implementedFinders' => [
                'slugged' => 'findSlug',
                'check' => 'checkExist']
        ]);

  field: name of field hold original string
  slug: name of field will save slugged string
  replacement: the connector character
  slugged: alias of function findSlug, you can change to new one. VD: 'friendlyName' => 'findSlug'
  check: alias of function checkExist, you can change to new one. VD: 'checkExisting' => 'checkExist'

Ex1: 
$article = \Cake\ORM\TableRegistry::get('Articles')->find('slugged', ['slug' => 'how-to-make-friendly-url'])->first();
Ex2:
$this->loadModel('Articles');
$article = $this->Articles->find('slugged', ['slug' => 'how-to-make-friendly-url'])->first();
Ex3:
$isExist = $this->Articles->find('check', ['slug' => 'how-to-make-friendly-url'])->first();
if($isExist)
        do_some_thing;
else
        save entity;