# fields_for_app simple demo app for troubleshooting issue github.com/rails/rails/issues/27031
# usage There are two models: product that has many components.
Product validates name to include mandatory word card. Components that build product can be either envelope or paper.
If one enters some data that are unvalid, only components that are within scopes ‘papers` or `envelopes` are shown, on either #create or #update actions. Expected behavior would be to show all components in rendered form.