diff --git a/app/models.py b/app/models.py
index a3ebd6ec..a88dd6dc 100644
--- a/app/models.py
+++ b/app/models.py
@@ -100,7 +100,12 @@ class User(db.Model, ModelMixin, UserMixin):
     password = db.Column(db.String(128), nullable=False)
     name = db.Column(db.String(128), nullable=False)
     is_admin = db.Column(db.Boolean, nullable=False, default=False)
-    alias_generator = db.Column(db.Integer, nullable=False, default=AliasGeneratorEnum.word.value)
+    alias_generator = db.Column(
+        db.Integer,
+        nullable=False,
+        default=AliasGeneratorEnum.word.value,
+        server_default=str(AliasGeneratorEnum.word.value),
+    )
 
     activated = db.Column(db.Boolean, default=False, nullable=False)
 
@@ -321,8 +326,8 @@ class Client(db.Model, ModelMixin):
     def last_user_login(self) -> "ClientUser":
         client_user = (
             ClientUser.query.filter(ClientUser.client_id == self.id)
-                .order_by(ClientUser.updated_at)
-                .first()
+            .order_by(ClientUser.updated_at)
+            .first()
         )
         if client_user:
             return client_user
@@ -378,7 +383,9 @@ class OauthToken(db.Model, ModelMixin):
         return self.expired < arrow.now()
 
 
-def generate_email(scheme: int = AliasGeneratorEnum.word.value, in_hex: bool = False) -> str:
+def generate_email(
+    scheme: int = AliasGeneratorEnum.word.value, in_hex: bool = False
+) -> str:
     """generate an email address that does not exist before
     :param scheme: int, value of AliasGeneratorEnum, indicate how the email is generated
     :type in_hex: bool, if the generate scheme is uuid, is hex favorable?
@@ -391,7 +398,7 @@ def generate_email(scheme: int = AliasGeneratorEnum.word.value, in_hex: bool = F
 
     # check that the client does not exist yet
     if not GenEmail.get_by(email=random_email) and not DeletedAlias.get_by(
-            email=random_email
+        email=random_email
     ):
         LOG.debug("generate email %s", random_email)
         return random_email
@@ -431,7 +438,9 @@ class GenEmail(db.Model, ModelMixin):
         return GenEmail.create(user_id=user_id, email=email)
 
     @classmethod
-    def create_new_random(cls, user_id, scheme: int = AliasGeneratorEnum.word.value, in_hex: bool = False):
+    def create_new_random(
+        cls, user_id, scheme: int = AliasGeneratorEnum.word.value, in_hex: bool = False
+    ):
         """create a new random alias"""
         random_email = generate_email(scheme=scheme, in_hex=in_hex)
         return GenEmail.create(user_id=user_id, email=random_email)
@@ -570,8 +579,8 @@ class ForwardEmail(db.Model, ModelMixin):
         """return the most recent reply"""
         return (
             ForwardEmailLog.query.filter_by(forward_id=self.id, is_reply=True)
-                .order_by(desc(ForwardEmailLog.created_at))
-                .first()
+            .order_by(desc(ForwardEmailLog.created_at))
+            .first()
         )
 
 
diff --git a/migrations/versions/2019_122521_8f53e718c79a_alias_generator_scheme.py b/migrations/versions/2019_122521_8f53e718c79a_alias_generator_scheme.py
index 96bf621a..6099b453 100644
--- a/migrations/versions/2019_122521_8f53e718c79a_alias_generator_scheme.py
+++ b/migrations/versions/2019_122521_8f53e718c79a_alias_generator_scheme.py
@@ -9,7 +9,6 @@ import sqlalchemy_utils
 from alembic import op
 import sqlalchemy as sa
 
-
 # revision identifiers, used by Alembic.
 revision = '8f53e718c79a'
 down_revision = '9e1b06b9df13'
@@ -19,7 +18,7 @@ depends_on = None
 
 def upgrade():
     # ### commands auto generated by Alembic - please adjust! ###
-    op.add_column('users', sa.Column('alias_generator', sa.Integer(), nullable=False))
+    op.add_column('users', sa.Column('alias_generator', sa.Integer(), server_default="1", nullable=False))
     # ### end Alembic commands ###