How to add Column in existing table in asp Boilerplate?

As you know Boilerplate don't give the entity classes to add columns and I want to add column in table named ( AbpUser). I tried to make a class in Migrations like below

public partial class AddRatingMig : DbMigration
{
    public override void Up()
    {
        AddColumn("dbo.AbpUsers", "UserType", c => c.String());
    }

    public override void Down()
    {
        DropColumn("dbo.AbpUsers", "UserType");
    }
}

Then in Pm console run command Update-Database . But not successful. As you know Boilerplate don't give the entity classes to edit columns. Please Help Thanks in advance

The answer to this question is to Extend the AbpUser like this

public class User : AbpUser<User> 
{ 
    public string SpecialTitle { get; set; } 
}

and add-migration UpdatedUserWithSpecialTitle then update-database