How do I migrate model changes in pylons/sqlalchemy?

I created a simple model and then mapped it to a class using sqlalchemy in pylons:

tag_table = schema.Table('tag', meta.metadata,
    schema.Column('id', types.Integer,
                  schema.Sequence('tag_seq_id', optional=True),
                  primary_key=True),
    schema.Column('name', types.Unicode(20), nullable=False, unique=True),
)

class Tag(object):
    pass
orm.mapper(Tag, tag_table)

When I run paster setup-app development.ini I can see that the table is created but if I add another column to my table, how do I migrate the only column 开发者_运维问答that I've added?

I've seen this migration in Rails and Django but is there something similar for Pylons?

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You can try this tool: sqlalchemy-migrate