title: October cms, cant save model with empty values
body: <p>I cretead model, with columns: </p>
  
  <p><strong>like4u_id, vtope_id, panel_id</strong></p>
  
  <p>I set these columns option - Nullable, but if i save model, i get error:</p>
  
  <blockquote>
    <p>SQLSTATE[HY000]: General error: 1366 Incorrect integer value: '' for
    column 'like4u_id' at row 1 (SQL: update
    <code>master_vars</code> set <code>updated_at</code> = 2018-05-23
    16:03:14, <code>like4u_id</code> = , <code>vtope_id</code> =  where <code>id</code> = 328)</p>
  </blockquote>
  
  <p>What is the problem? It's field not required and column nullable..</p>