```ruby
class CreateMaps < ActiveRecord::Migration
  def change
    create_table :maps do |t|
      t.string :name
      t.string :string

      t.timestamps null: false
    end
  end
end
```

Remove string field for maps table
user
```ruby
class CreateMaps < ActiveRecord::Migration
  def change
    create_table :maps do |t|
      t.string :name

      t.timestamps null: false
    end
  end
end
```
assistant