title: Eloquent saves missing attributes as empty strings instead of NULLs
body: <p>When I try to save a model with a missing attribute to a not-NULL db field, I don't want the application to be quiet about that, I want it to scream in vein. But it's being just fine with the empty strings that eloquent saves.</p>
  
  <p>Why does <code>MyModel::create([])</code> succeed??</p>