Added FK's for the department table.
Added FK's for the department table.

andrewmoko/openmrs-module-openhmis.cashier,k-joseph/openmrs-module-openhmis.cashier,k-joseph/openmrs-module-openhmis.cashier,k-joseph/openmrs-module-openhmis.cashier,andrewmoko/openmrs-module-openhmis.cashier,andrewmoko/openmrs-module-openhmis.cashier