Update buy_book.rb

We also need to mofidy "buy_book.rb" again as following:

cd ../step_definitions/

# encoding: utf-8
Given /^I open "(.*?)"$/ do |site|
    @home.openSite (site)
end

And /^I login as "(.?)" with "(.?)"$/ do |username,password|
    @login.loginAs(username,password)
end
When /^I search for "(.*?)"$/ do |keyword|
    @page.searchByKeyword (keyword)
end
And /^I open the first book$/ do
    @searchresult.openTheFirstItemInSearchResult
end
And /^I add the first book to Wish List$/ do
    @itemdetails.getCurrentItemTitle
    @itemdetails.addToWishList
end
And /^I add the first book to shopping cart$/ do
    @itemdetails.getCurrentItemTitle
    @itemdetails.addToShoppingCart
end
And /^I add the first book to shopping cart from Wish List$/ do
    @itemdetails.openWishList
    @wishlist.addToShoppingCartFromWishList
end
And /^I open my shopping cart$/ do
    @wishlist.openShoppingCart
end
Then /^I should see the book in my shopping cart$/ do
    @shoppingcart.verifyItemAddedToShoppingCart
    @shoppingcart.verifyItemAddedShownInShoppingCart
end