invoice_keeper/db/migrate/20160930095557_create_customers.rb

class CreateCustomers < ActiveRecord::Migration[5.0]
  def change
    create_table :customers do |t|
      t.string :name
      t.string :street
      t.string :postcode
      t.string :city
      t.string :nip
      t.string :regon

      t.timestamps
    end
  end
end