```ruby
Sequel.migration do
  change do
    create_table :user_notifications do
      foreign_key :user_id, :users, type: :uuid, null: false, on_delete: :cascade, primary_key: true
      String :notifications, null: false, type: 'json'
    end
  end
end
```

Add default to user notifications
user
```ruby
Sequel.migration do
  change do
    create_table :user_notifications do
      foreign_key :user_id, :users, type: :uuid, null: false, on_delete: :cascade, primary_key: true
      String :notifications, null: false, type: 'json', default: '{}'
    end
  end
end
```
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