void FindForks()
{
variationMapping = QueryEvent.GetVariantCodeMapping(eventDB, new CourseDesignator(courseId));
// Find all forks.
allForks = new List<Fork>();
Id<CourseControl> firstCourseControlId = eventDB.GetCourse(courseId).firstCourseControl;
firstForkInCourse = FindForksToJoin(firstCourseControlId, Id<CourseControl>.None);
}