move devise views to users views
generate Food model, controller and migration files
add 'category' column to 'foods' table
require authentication for 'foods' controller
remove 'foods' controller. add validations for 'foods' and users'. create view for 'foods' based on selected 'category'
validations for 'food' model. remove 'order' action from 'pages' controller. create 'order' model. create join model 'order_foods'.
Minor changes to 'orders' controller
add feature for adding foods to an order when creating that order

using virtual attributes to create Order which has a many to many
relationship with Food