title: Eloquent model returns 0 as primary key
body: <p>I have this migration:</p>
  
  <pre><code>Schema::create('provincias', function (Blueprint $table) {
      $table-&gt;string('codigo', 2);
      $table-&gt;string('nombre', 50);
      $table-&gt;timestamp('creado');
      $table-&gt;primary('codigo');
  });
  </code></pre>
  
  <p>This is my model:</p>
  
  <pre><code>class Provincia extends Model
  {   
      protected $primaryKey = 'codigo';
      public $timestamps = false;
  }
  </code></pre>
  
  <p>I run the migration and save data like this:</p>
  
  <pre><code>$provincia = new Provincia;
  $provincia-&gt;codigo = "BA";
  $provincia-&gt;nombre = "Buenos Aires";
  $provincia-&gt;save();
  </code></pre>
  
  <p>The problem is that when I get all and dump:</p>
  
  <pre><code>$provincias = Provincia::all();
  return $provincias;
  </code></pre>
  
  <p>The primary key "codigo" is always 0 even when I check the database table and it has the proper value:</p>
  
  <pre><code>{
      codigo: 0,
      nombre: "Buenos Aires",
      creado: "2015-12-24 21:00:24"
  }
  </code></pre>