Adding int property, EF keeps making it nullable column?

I'm adding a int property called Order to an existing entity that already has records in the DB tables.

public class Page : Content
{
    // ...
    public int Order { get; set; }
    // ...

}

However, when I run "update-database", it's adding the column as nullable with a default value of null. I tried using [DefaultValue(0)], as well as setting the default in the constructor. Neither work.

How can I add a column/property to an existing set of data and have it populate as a non-null value of 0? Thanks.