title: add field in customer table nopcommerce 3.3
body: <p>I am studying nopcommerce 3.3 and MVC 4 in also newer for me. I am learning this.<br> 
  So I want to add new field in customer table that is <code>AlternateEmail</code>. 
  I have add this field in Database then Customer model and in view but it gives me error that </p>
  
  <blockquote>
    <p><code>Nop.Admin.Models.Customers.CustomerModel</code> does not contain a
    definition for 'AlternateEmail` and no extension method
    'AlternateEmail' accepting a first argument of type
    'Nop.Admin.Models.Customers.CustomerModel' could be found (are you
    missing a using directive or an assembly reference?)"</p>
  </blockquote>
  
  <p>Where I am missing?</p>