Challenge 1: A Product Form — Solution

<!-- app/views/products/_form.html.erb -->
<%= form_with model: product do |f| %>
  <%= f.label :name %>
  <%= f.text_field :name %>

  <%= f.label :description %>
  <%= f.text_area :description %>

  <%= f.label :in_stock %>
  <%= f.check_box :in_stock %>

  <%= f.submit %>
<% end %>

=begin
Notes:
- form_with model: product handles both the new-product and
  edit-product cases with this single partial -- if product is a new,
  unsaved record, the form POSTs to /products (create); if it's an
  existing, persisted record, it submits as PATCH to /products/:id
  (update), all decided automatically from the object's own state.
- f.text_field, f.text_area, and f.check_box each generate their
  appropriate HTML input type, all automatically named
  product[name], product[description], and product[in_stock]
  respectively -- matching the nested params structure a
  product_params strong-parameters method (Challenge 2) would expect.
- f.submit with no arguments generates a submit button whose label
  automatically reads "Create Product" or "Update Product" depending on
  whether product is new or already persisted, again inferred rather
  than hardcoded.
=end