title: How Active Record validation check, if type is array?
body: <p>I have attribute user`s languages. When form submit, it must return array?</p>
  
  <p>I want to write validation in model User:</p>
  
  <p><code>validates :languages, presence: true</code></p>
  
  <p>How write in validates, returning value must be is array? </p>