PG add not null values column with array type

add_column_as_array.sql

ALTER TABLE users
ADD COLUMN positions INTEGER[] NULL;

UPDATE users SET positions = '{}';

ALTER TABLE users
ALTER COLUMN positions SET NOT NULL;

-- +-----------------+--------------------------+----------------------------------------------------------+
-- | Column          | Type                     | Modifiers                                                |
-- |-----------------+--------------------------+----------------------------------------------------------|
-- | ...             | ...                      |  ...                                                     |
-- | positions       | integer[]                |  not null                                                |
-- +-----------------+--------------------------+----------------------------------------------------------+