add rspec,rspec-rails
 install 2 gems
and bundle update
rails g rspec:install
rails g scaffold Product_new title description:text image_url price:decimal
rake db:migrate
add model rspec
rspec  spec/models/product_new_spec.rb
rspec 3 use "expect" instead "should" .....
bug fix
note:use be_truthy instead be_true
see:
https://relishapp.com/rspec/rspec-core/docs/example-groups/shared-examples