Fix FinalSeminarSchedulingTest

It previously did not populate all the required attributes that were checked using NOT NULL constraints in the migration scripts but were not present in the Hibernate generated DDL for HSQLDB.

core/src/test/java/se/su/dsv/scipro/finalseminar/FinalSeminarSchedulingTest.java

@@ -197,6 +197,7 @@ public class FinalSeminarSchedulingTest extends IntegrationTest {
         NonWorkDayPeriod nonWorkDayPeriod = new NonWorkDayPeriod();
         nonWorkDayPeriod.setStartDate(date);
         nonWorkDayPeriod.setEndDate(date);
+        nonWorkDayPeriod.setComment("test non work day");
         save(nonWorkDayPeriod);
     }