title: Rails 5 check if record exist in belongs_to relations?
body: <p>I have 3 models Account, Plan and User (And I can not modify the relations model structure, but add scopes or methods)</p>
  
  <pre><code>Account 
  belongs_to :plan
  
  Plan
  belongs_to :user
  
  User
  has_may :plans
  </code></pre>
  
  <p>I want to know if EXISTS an account with a specific user_id</p>
  
  <p>Account.exists?…….. //here is my problem</p>