```ruby
class ResizeApiKeyField < ActiveRecord::Migration
  def change
    change_column :spree_users, :api_key, :string, :limit => 48
  end
end
```

Check if User is defined on ResizeApiKeyField Migration (like others)
user
```ruby
class ResizeApiKeyField < ActiveRecord::Migration
  def change
    unless defined?(User)    
      change_column :spree_users, :api_key, :string, :limit => 48
    end
  end
end
```
assistant