Parent
<%= activerecord_migration_class %> def change create_table :mobility_string_translations do |t| t.string :locale, null: false t.string :key, null: false t.string :value t.references :translatable, polymorphic: true, index: false t.timestamps null: false end add_index :mobility_string_translations, [:translatable_id, :translatable_type, :locale, :key], unique: true, name: :index_mobility_string_translations_on_keys add_index :mobility_string_translations, [:translatable_id, :translatable_type, :key], name: :index_mobility_string_translations_on_translatable_attribute add_index :mobility_string_translations, [:translatable_type, :key, :value, :locale], name: :index_mobility_string_translations_on_query_keys end end