Queue object implemented in Ruby

Queue.rb

class Queue
        include Enumerable

        attr_reader :queue

        def initialize
                @queue = Array.new
        end

        #enqueue(item) adds item to the end of the queue
        def enqueue(item)
                @queue.unshift(item)
        end

        #dequeue removes the item at the front of the queue. It returns the removed item.
        def dequeue
                @queue.pop
        end

        def size
                @queue.length
        end

        def empty?
                size == 0 ? true : false        
        end
        
        def include?(item)
                @queue.include?(item) ? true : false
        end

        #extends each method to class Queue per http://stackoverflow.com/questions/2080007/how-do-i-add-each-method-to-ruby-object-or-should-i-extend-array
        def each(&block)
                @queue.each(&block)
        end
end