Add the foreign key constraint of year and quarter to Limits

In order to update the existing database, use:

 ALTER TABLE Limits ADD CONSTRAINT Limits_Quarter FOREIGN KEY Limits_Quarter (year,quarter) REFERENCES Quarter (year,quarter);

src/main/resources/sql/createtables.sql

 -- Created by Vertabelo (http://vertabelo.com)
--- Last modification date: 2018-05-30 13:26:29.23
+-- Last modification date: 2018-06-01 10:26:52.542
 
 -- tables
 -- Table: Availability
@@ -311,6 +311,10 @@ ALTER TABLE LabTimeslot ADD CONSTRAINT LabTimeslot_Lab FOREIGN KEY LabTimeslot_L
 ALTER TABLE LabTimeslot ADD CONSTRAINT LabTimeslot_Timeslot FOREIGN KEY LabTimeslot_Timeslot (date,slot_id)
     REFERENCES Timeslot (date,slot_id);
 
+-- Reference: Limits_Quarter (table: Limits)
+ALTER TABLE Limits ADD CONSTRAINT Limits_Quarter FOREIGN KEY Limits_Quarter (year,quarter)
+    REFERENCES Quarter (year,quarter);
+
 -- Reference: Limits_User (table: Limits)
 ALTER TABLE Limits ADD CONSTRAINT Limits_User FOREIGN KEY Limits_User (netid)
     REFERENCES User (netid);