backref='encounter_map')
EncounterSlot.terrain = relation(EncounterTerrain, backref='slots')
+EncounterSlot.version_group = relation(VersionGroup)
EncounterSlot.condition_map = relation(EncounterSlotCondition, backref='slot')
EncounterSlot.conditions = association_proxy('condition_map', 'condition')