Need help with a ruby on rails bike rental application

class CartController < ApplicationController
  before_action :authenticate_user!


  def add
    # get the ID of the product
    id = params[:id]

    # if the cart is already been created, use the existing cart
    # else create a blank cart
    if session[:cart] then
      cart = session[:cart]
    else
      session[:cart] = {}
      cart = session[:cart]
    end

    # if the product has already been added to the cart, increment the value
    # else set the value to 1
    if cart[id] then
      cart[id] = cart[id] + 1
    else
      cart[id] = 1
    end

    # redirect to the cart display page
    redirect_to :action => :index

  end

  def clearCart
    # set the session variable to nil and redirect
    session[:cart] = nil
    redirect_to :action => :index
  end 

  def index
    # if there is a cart, pass it to the page for display
    # else pass an empty value
    if session[:cart] then
      @cart = session[:cart]
    else
      @cart = {}
    end
  end

end

class ItemsController < ApplicationController
  before_action :authenticate_user!
  before_action :ensure_admin, :only => [:edit, :destroy]
  before_action :set_item, only: [:show, :edit, :update, :destroy]

  # GET /items Only admin can edit delete items
  # GET /items.json
  def index
    @items = Item.all
  end

  # GET /items/1
  # GET /items/1.json
  def show
  end

  # GET /items/new
  def new
    @item = Item.new
  end

  # GET /items/1/edit
  def edit
  end

  # POST /items
  # POST /items.json
  def create

    puts "debug +++++++++++++++++++++++++++++++++++++++++++++++++++"
    puts params.inspect
    puts "debug +++++++++++++++++++++++++++++++++++++++++++++++++++"

    @item = Item.new(item_params)

    respond_to do |format|
      if @item.save
        format.html { redirect_to @item, notice: 'Item was successfully created.' }
        format.json { render :show, status: :created, location: @item }
      else
        format.html { render :new }
        format.json { render json: @item.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /items/1
  # PATCH/PUT /items/1.json
  def update
    respond_to do |format|
      if @item.update(item_params)
        format.html { redirect_to @item, notice: 'Item was successfully updated.' }
        format.json { render :show, status: :ok, location: @item }
      else
        format.html { render :edit }
        format.json { render json: @item.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /items/1
  # DELETE /items/1.json
  def destroy
    @item.destroy
    respond_to do |format|
      format.html { redirect_to items_url, notice: 'Item was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  def ensure_admin
    unless current_user && current_user.admin?
      render :text => "Access Error Message", :status => :unauthorized
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_item
      @item = Item.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def item_params
      params.require(:item).permit(:title, :description, :price, :image_url, :category, :brand)
    end
end

<h1>Your Cart</h1>

<% if @cart.empty? %>
    <p>Your Cart is empty</p>
<% end %>

<% total = 0 %>

<table class="cart">
    <tr>
        <td class="legend"></td>
        <td class="legend">Item</td>
        <td class="legend">Price</td>
        <td class="legend">Length</td>
        <td class="legend">Total</td>
    </tr>

<% @cart.each do | id, quantity | %>
    <% item = Item.find_by_id(id) %>
    <tr>
        <td>
            <div class="image">
                <%= link_to (image_tag item.image_url, :style => "height:40px"), item %>
            </div>
        </td>
        <td class="title"><%= link_to item.title, item %></td>
        <td class="price"><%= number_to_currency(item.price) %></td>
        <td class="quantity"><%= quantity %><br /></td>
        <td class="price"><%= number_to_currency(quantity * item.price, :unit => "€") %></td>
            %input{:type =>'text', :placeholder => params[:startdate] != nil ? params[:startdate] : "from date", :id => 'startdate', :name => "startdate", :style => 'width: 100px'}
            %input{:type =>'text', :placeholder => params[:startdate] != nil ? params[:enddate] : "to date", :id => 'enddate', :name => "enddate", :style => 'width: 100px'}
    </tr>
    <% total += quantity * item.price %>
<% end %>

    <tr>
        <td colspan="4">
            <div class="total">Total:</div>
        </td>
        <td>
            <div class="price"><%= number_to_currency(total, :unit => "Eur") %></div>
        </td>
    </tr>
</table>

<p>
    <%= link_to 'Make a booking', :controller => :items %>
</p>

Rails.application.routes.draw do

  resources :bookings
  get 'bookings/index'

  get 'bookings/show'

  get 'bookings/new'

  get 'bookings/edit'

  get 'bookings/destroy'

  resources :profiles
 get 'bookings/index'

  get 'bookings/show'

  get 'bookings/new'

  get 'bookings/edit'

  get 'bookings/destroy'

  resources :profiles

  devise_for :users
  get '/about' => 'site#about'
  get '/contact' => 'site#contact'
  get '/admin' => 'user#admin_login'
  get '/logout' => 'user#logout'
  get '/cart' => 'cart#index' 
  get '/cart/:id' => 'cart#add'
  get '/cart/clear' => 'cart#clearCart' 
  get '/signedinuserprofile' => 'profiles#signedinuserprofile'
  get '/product' => 'catalog#view'

  resources :items

  # The priority is based upon order of creation: first created -> highest priority.
  # See how all your routes lay out with "rake routes".

  # You can have the root of your site routed with "root"
  root 'items#index'

  # Example of regular route:
     get 'products/:id' => 'catalog#view'

  # Example of named route that can be invoked with purchase_url(id: product.id)
     get 'products/:id/purchase' => 'catalog#purchase', as: :purchase

  # Example resource route (maps HTTP verbs to controller actions automatically):
  #   resources :products

  # Example resource route with options:
  #   resources :products do
  #     member do
  #       get 'short'
  #       post 'toggle'
  #     end
  #
  #     collection do
  #       get 'sold'
  #     end
  #   end

  # Example resource route with sub-resources:
  #   resources :products do
  #     resources :comments, :sales
  #     resource :seller
  #   end

  # Example resource route with more complex sub-resources:
  #   resources :products do
  #     resources :comments
  #     resources :sales do
  #       get 'recent', on: :collection
  #     end
  #   end

  # Example resource route with concerns:
  #   concern :toggleable do
  #     post 'toggle'
  #   end
  #   resources :posts, concerns: :toggleable
  #   resources :photos, concerns: :toggleable

  # Example resource route within a namespace:
  #   namespace :admin do
  #     # Directs /admin/products/* to Admin::ProductsController
  #     # (app/controllers/admin/products_controller.rb)
  #     resources :products
  #   end
end