feat: add created_at, modified_at in ticket_holder

app/models/ticket_holder.py

@@ -46,6 +46,8 @@ class TicketHolder(SoftDeletionModel):
     checkout_times: str = db.Column(db.String)
     attendee_notes: str = db.Column(db.String)
     event_id: int = db.Column(db.Integer, db.ForeignKey('events.id', ondelete='CASCADE'))
+    created_at: datetime = db.Column(db.DateTime(timezone=True), default=datetime.utcnow)
+    modified_at: datetime = db.Column(db.DateTime(timezone=True), default=datetime.utcnow,  onupdate=datetime.utcnow)
     complex_field_values: str = db.Column(db.JSON)
     user = db.relationship('User', foreign_keys=[email], primaryjoin='User.email == TicketHolder.email', viewonly=True,
                            backref='attendees')

migrations/versions/rev-2019-12-13-20:34:35-8621f70992ba_.py

@@ -0,0 +1,30 @@
+"""empty message
+
+Revision ID: 8621f70992ba
+Revises: 0223c881d135
+Create Date: 2019-12-13 20:34:35.014066
+
+"""
+
+from alembic import op
+import sqlalchemy as sa
+import sqlalchemy_utils
+
+
+# revision identifiers, used by Alembic.
+revision = '8621f70992ba'
+down_revision = '0223c881d135'
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('ticket_holders', sa.Column('created_at', sa.DateTime(timezone=True), nullable=True))
+    op.add_column('ticket_holders', sa.Column('modified_at', sa.DateTime(timezone=True), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('ticket_holders', 'modified_at')
+    op.drop_column('ticket_holders', 'created_at')
+    # ### end Alembic commands ###