ensure task.expiration is always set(cannot be null)

pybossa/repositories/task_repository.py

@@ -34,6 +34,7 @@
 from flask import current_app
 from sqlalchemy import or_
 from sqlalchemy.sql import case as sqlalchemy_case
+from pybossa.task_creator_helper import get_task_expiration
 
 
 class TaskRepository(Repository):
@@ -179,6 +180,8 @@ def _filter_query(self, query, obj, limit, offset, last_id, yielded, desc):
     def save(self, element, clean_project=True):
         self._validate_can_be(self.SAVE_ACTION, element)
         try:
+            # set default expiration
+            element.expiration = get_task_expiration(element.expiration, make_timestamp())
             self.db.session.add(element)
             self.db.session.commit()
             if clean_project: