title: PetPoco Mapping ignore column
body: <p>I am doing an insert into a table using petapoco. The insert was working fine until I introduced a property on the class that was calculated and didn't map to any column in the table. Now the code breaks because it is not able to map that property(isAdmin) to a column in the table. I tried adding the attribute [PetaPoco.Ignore] to the class property isAdmin but that didnt help.</p>
  
  <p>This is how I am doing the mapping</p>
  
  <pre><code> For&lt;Users&gt;()
                  .TableName("users")
                  .PrimaryKey("id",false)
                  .Columns(x =&gt;
                  {
                      x.Column(y =&gt; y.id, "id");
                      x.Column(y =&gt; y.UserType, "user_type");
                      x.Column(y =&gt; y.isAdmin,"");//How do I tell petapoco not to map this to any column?
                  });
  </code></pre>