Adding composite unique constraint in Liquibase

You can read liquibase manual also similar problem you can find here

In your case it should be:

<changeSet author="liquibase-docs" id="addUniqueConstraint-example">
<addUniqueConstraint
        columnNames="product_id, tournament_id"
        constraintName="your_constraint_name"
        tableName="person"
        />
</changeSet>