class CreateGroups < ActiveRecord::Migration
  def change
    create_table :groups do |t|
      t.string :name, null: false
      t.string :address, null: false

      t.timestamps null: false
    end
  end
end

class CreateGroups < ActiveRecord::Migration
  def change
    create_table :groups do |t|
      t.integer :number,   null: false
      t.string  :street,   null: false
      t.string  :city,     null: false
      t.integer :zip_code, null: false

      t.timestamps null: false
    end
  end
end

Change groups migration so that the attributes we expect are saved.
Change groups migration so that the attributes we expect are saved.

Note that the name is no longer a field on our group table, but it is a
virtual attribute in our model. We no longer have uniqueness validations
at the Model level or constraints at the Database level.
