PaginatableArray can be instantiated without an argument

lib/kaminari/models/array_extension.rb

@@ -9,7 +9,7 @@ module Kaminari
     # * <tt>:limit</tt> - limit
     # * <tt>:offset</tt> - offset
     # * <tt>:total_count</tt> - total_count
-    def initialize(original_array, options = {})
+    def initialize(original_array = [], options = {})
       @_original_array, @_limit_value, @_offset_value, @_total_count = original_array, (options[:limit] || default_per_page).to_i, options[:offset].to_i, options[:total_count]
 
       if options[:limit] && options[:offset]

spec/models/array_spec.rb

@@ -1,6 +1,8 @@
 require File.expand_path('../spec_helper', File.dirname(__FILE__))
 
 describe Kaminari::PaginatableArray do
+  it { should have(0).items }
+
   context 'specifying limit and offset when initializing' do
     subject { Kaminari::PaginatableArray.new((1..100).to_a, :limit => 10, :offset => 20) }
     its(:current_page) { should == 3 }