Reached page 125. Things are going fine. Thank you Sam, Dave and David. The Ajaxifying of cart worked perfectly.
There is one minor comment and I believe it needs a change in the store controller. This is how the empty_cart method (in depot_l/app/controllers/store/store_controller.rb) looks like:
def empty_cart session[:cart] = nil redirect_to_index("Your cart is currently empty") end
What happens because of this redirect and now that cart addition is Ajaxified is that even after adding an item to cart, the flash from a previous emptying of cart remains at the top of index page! This is because add_to_cart no more fetches the index page, but just updates side bar.
I believe the code should be changed thus:
def empty_cart session[:cart] = nil redirect_to_index end
Thank you, Kedar