Changed USER::addStudentCourse(string $subj, int $crse) o USER::addUserCourse(string $rel, string $subj, int $crse) and SER::removeStudentCourse(string $subj, int $crse) to USER::removeStudentCourse(string $rel, tring $subj, int $crse). This change will allow the editing of either student-course or ta-course relations in the database by passing "ta" or "student" in $rel.