Apparently, teacher does not have the value in the DB yet

No tests added though

Conversion added to gender, period and ethnic group

Now you can join tables with composite foreign/primary keys using RQF. In the
join attribute just use an array of columns that need to be used in the join

* Create routes /enrollment/gender and /enrollment/ethnic_group
* Add gender and ethnic_group to enrollment params in RQF

SQL now is using new schema

SQL is now compatible with DB schema in simcaqdb3