vendor/rails/railties/lib/rails_generator/generators/components/migration/templates/migration.rb

   1 class <%= class_name.underscore.camelize %> < ActiveRecord::Migration
   2   def self.up<% attributes.each do |attribute| %>
   3     <%= migration_action %>_column :<%= table_name %>, :<%= attribute.name %><% if migration_action == 'add' %>, :<%= attribute.type %><% end -%>
   4   <%- end %>
   5   end
   6
   7   def self.down<% attributes.reverse.each do |attribute| %>
   8     <%= migration_action == 'add' ? 'remove' : 'add' %>_column :<%= table_name %>, :<%= attribute.name %><% if migration_action == 'remove' %>, :<%= attribute.type %><% end -%>
   9   <%- end %>
  10   end
  11 end