public class Course
{
    public int Id {get; set;}
    public Curriculum { get; set; }
}


public class Curriculum
{
    [ForeignKey("Course")]
    public int Id { get; set; }

    pubic Course Course { get; set; }
}

public class CourseConfiguration : EntityTypeConfiguration<Course>
{
    public CourseConfiguration()
    {
        HasOptional(course => course.Curriculum)
            .WithRequired(cur => cur.Course);
    }
}