categories and products panels are only accesible by administrators
add links for managing categories and products on main template
install moltin laravel cart package after modifying composer.json and run 'composer.update'
now we'll be able to use Cart class and its various static method
only authenticate users can access actions that involves a cart
controller actions for add products to cart, view the content of a cart, remove a cart item
create cart form view and make links to add products to the cart