Add migration to add slug DB field to order

app/migrations/versions/29ccbe077c57_add_slug.py

@@ -0,0 +1,23 @@
+"""add slug
+
+Revision ID: 29ccbe077c57
+Revises: 55013fe95bea
+Create Date: 2022-05-20 19:46:11.924218
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '29ccbe077c57'
+down_revision = '55013fe95bea'
+
+from alembic import op
+import sqlalchemy as sa
+
+def upgrade():
+    op.add_column('order', sa.Column('slug', sa.String(length=7), nullable=True))
+    op.create_unique_constraint(None, 'order', ['slug'])
+
+
+def downgrade():
+    op.drop_constraint(None, 'order', type_='unique')
+    op.drop_column('order', 'slug')