Fix the default value for comma separated lists

admin/freeposte/admin/models.py

@@ -135,7 +135,7 @@ class User(Email):
 
     # Filters
     forward_enabled = db.Column(db.Boolean(), nullable=False, default=False)
-    forward_destination = db.Column(CommaSeparatedList, nullable=True, default=None)
+    forward_destination = db.Column(CommaSeparatedList, nullable=True, default=[])
     reply_enabled = db.Column(db.Boolean(), nullable=False, default=False)
     reply_subject = db.Column(db.String(255), nullable=True, default=None)
     reply_body = db.Column(db.Text(), nullable=True, default=None)
@@ -189,7 +189,7 @@ class Alias(Email):
     """
     domain = db.relationship(Domain,
         backref=db.backref('aliases', cascade='all, delete-orphan'))
-    destination = db.Column(CommaSeparatedList, nullable=False)
+    destination = db.Column(CommaSeparatedList, nullable=False, default=[])
 
 
 class Fetch(Base):