zammad/db/migrate/20170912123300_remove_network.rb

class RemoveNetwork < ActiveRecord::Migration[5.0]

  # rewinds db/migrate/20120101000020_create_network.rb
  def change
    return if !ActiveRecord::Base.connection.table_exists? 'networks'

    drop_table :networks
    drop_table :network_category_types
    drop_table :network_privacies
    drop_table :network_categories
    drop_table :network_categories_moderator_users
    drop_table :network_items
    drop_table :network_item_comments
    drop_table :network_item_plus
    drop_table :network_category_subscriptions
    drop_table :network_item_subscriptions
  end
end