Fix: Add default value. (Redmine issue: #7106)

lib/hawat/migrations/versions/c2b4c2af6196_removed_groups_managed.py

@@ -21,4 +21,4 @@ def upgrade():  # pylint: disable=locally-disabled,missing-docstring
 
 
 def downgrade():  # pylint: disable=locally-disabled,missing-docstring
-    op.add_column('groups', sa.Column('managed', sa.BOOLEAN(), autoincrement=False, nullable=False))
+    op.add_column('groups', sa.Column('managed', sa.BOOLEAN(), autoincrement=False, nullable=False, default=False, server_default='f'))