add cron for contract expiration

contract.py

@@ -149,10 +149,12 @@ class Contract(Workflow, ModelSQL, ModelView):
     @Workflow.transition('draft')
     def draft(cls, contracts):
         contract = contracts[0]
+        contract.state = 'closed'
         for equipment in contract.equipments:
             equipment.state = "uncontrated"
             equipment.contract_history += (contract.id,)
             equipment.save()
+        contract.save()
 
     @classmethod
     @ModelView.button