A teacher can set that database activity entries require approval before being viewable by everyone

1. Login as a teacher, update a database activity and set 'Require approval' to Yes.
2. Login as student1 and add an entry.
3. Login as student2 and check that student1's entry is not visible.
4. Login as a teacher and approve student1's entry.
5. Login as student2 and check that student1's entry is now visible.